User Guide for Hotels
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User Guide for Hotels
Version 1.1
International Finance Corporation
Last Modified 2015.04.30
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[Type text]
International Finance Corporation
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TABLE OF CONTENTS
TABLE OF CONTENTS
TABLE OF CONTENTS ................................................................................................................................................ 3
LIST OF FIGURES ....................................................................................................................................................... 5
LIST OF TABLES ......................................................................................................................................................... 6
ACRONYMS ............................................................................................................................................................... 7
INTRODUCTION ........................................................................................................................................................ 8
DESIGN PAGE GUIDANCE ....................................................................................................................................... 10
GREEN MEASURES GUIDANCE ............................................................................................................................... 13
TECHNICAL GUIDANCE ........................................................................................................................................... 15
ENERGY EFFICIENCY MEASURES............................................................................................................................. 17
HTE01 – REDUCED WINDOW TO WALL RATIO ....................................................................................................... 18
HTE02 – EXTERNAL SHADING DEVICES .................................................................................................................. 20
HTE03 – INSULATION OF ROOF SURFACES ............................................................................................................ 24
HTE04 – INSULATION OF EXTERNAL WALLS ........................................................................................................... 27
HTE05 – LOW-E COATED GLASS ............................................................................................................................. 30
HTE06 – HIGHER THERMAL PERFORMANCE GLASS ............................................................................................... 32
HTE07 – NATURAL VENTILATION – CORRIDORS .................................................................................................... 34
HTE08 – NATURAL VENTILATION – GUEST ROOMS WITH AUTO CONTROL .......................................................... 37
HTE09 – VARIABLE REFRIGERANT VOLUME (VRV) COOLING SYSTEM ................................................................... 40
HTE10 – AIR CONDITIONING WITH AIR COOLED SCREW CHILLER ......................................................................... 42
HTE11 – AIR CONDITIONING WITH WATER COOLED CHILLER ............................................................................... 44
HTE12 – (GEOTHERMAL) GROUND SOURCE HEAT PUMP ...................................................................................... 46
HTE13 – ABSORPTION CHILLER POWERED BY WASTE HEAT .................................................................................. 49
HTE14 – RECOVERY OF WASTE HEAT FROM THE GENERATOR FOR SPACE HEATING............................................ 51
HTE15 – VARIABLE SPEED DRIVES ON THE FANS ON COOLING TOWERS .............................................................. 53
HTE16 – VARIABLE SPEED DRIVES PUMPS ............................................................................................................. 55
HTE17 – SENSIBLE HEAT RECOVERY FROM EXHAUST AIR ...................................................................................... 57
HTE18 – HIGH EFFICIENCY CONDENSING BOILER FOR SPACE HEATING ................................................................ 59
HTE19 – HIGH EFFICIENCY BOILER FOR WATER HEATING ..................................................................................... 61
HTE20 – VARIABLE SPEED HOODS WITH AUTOMATED FAN CONTROLS ............................................................... 63
HTE21 – PREHEAT WATER USING WASTE HEAT FROM THE GENERATOR ............................................................. 65
HTE22 – HEAT RECOVERY FROM GREY WATER ...................................................................................................... 66
HTE23 – HEAT RECOVERY FROM LAUNDRY WASTE WATER .................................................................................. 68
HTE24 – ENERGY – SAVING LIGHT BULBS – INTERNAL SPACES.............................................................................. 70
HTE25 – ENERGY – SAVING LIGHT BULBS – EXTERNAL SPACES ............................................................................. 72
HTE26 – ENERGY – SAVING LIGHT BULBS – BACK-OF-HOUSE ................................................................................ 74
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TABLE OF CONTENTS
HTE27 – LIGHTING CONTROLS FOR CORRIDORS ................................................................................................... 76
HTE28 – OCCUPANCY SENSORS IN BATHROOMS .................................................................................................. 78
HTE29 – SOLAR HOT WATER COLLECTORS ............................................................................................................ 80
HTE30 – SOLAR PHOTOVOLTAICS .......................................................................................................................... 82
WATER EFFICIENCY MEASURES ............................................................................................................................. 83
HTW01 – LOW-FLOW SHOWERHEADS IN GUEST ROOMS .................................................................................... 84
HTW02 – LOW-FLOW FAUCETS IN GUEST ROOMS................................................................................................ 85
HTW03 – DUAL FLUSH FOR WATER CLOSETS IN GUEST ROOMS .......................................................................... 86
HTW04 – WATER-EFFICIENT FRONT LOADING WASHING MACHINE .................................................................... 87
HTW05 – WATER-EFFICIENT URINALS IN ALL OTHER BATHROOMS ...................................................................... 88
HTW06 – DUAL FLUSH FOR WATER CLOSETS IN ALL OTHER BATHROOMS........................................................... 90
HTW07 – AERATORS & AUTO SHUT-OFF FAUCETS IN ALL OTHER BATHROOMS .................................................. 91
HTW08 – WATER- EFFICIENT DISHWASHERS ........................................................................................................ 93
HTW09 – PRE-RINSE VALVE FOR RINSING OPERATION ......................................................................................... 94
HTW10 – WATER EFFICIENT KITCHEN FAUCETS .................................................................................................... 95
HTW11 – WATER EFFICIENT LANDSCAPING .......................................................................................................... 96
HTW12 – SWIMMING POOL COVER ...................................................................................................................... 98
HTW13 – CONDENSATE WATER RECOVERY ........................................................................................................ 100
HTW14 – RAINWATER HARVESTING SYSTEM ...................................................................................................... 102
HTW15 – GREY WATER TREATMENT AND RECYCLING SYSTEM .......................................................................... 103
HTW16 – BLACK WATER TREATMENT AND RECYCLING ...................................................................................... 104
MATERIALS EFFICIENCY MEASURES .................................................................................................................... 105
HTM01 – FLOOR SLABS ........................................................................................................................................ 106
HTM02 – ROOF CONSTRUCTION ......................................................................................................................... 108
HTM03 – EXTERNAL WALLS ................................................................................................................................. 110
HTM04 – INTERNAL WALLS ................................................................................................................................. 114
HTM05 – FLOORING ............................................................................................................................................ 118
HTM06 – WINDOW FRAMES ............................................................................................................................... 120
HTM07 & HTM08 – INSULATION ......................................................................................................................... 121
REFERENCES......................................................................................................................................................... 123
APPENDIX 1: COUNTRY SPECIFIC CONSIDERATIONS ........................................................................................... 129
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TABLE OF CONTENTS
LIST OF FIGURES
Figure 1. Screenshot of energy saving measures for hotels in EDGE ..................................................................... 17
Figure 2. Relation between the Dh and Dv ............................................................................................................. 20
Figure 3. Typical Sources of Waste Heat and Recovery Options ........................................................................... 51
Figure 4. Schematic of cooling tower and VSD system ......................................................................................... 53
Figure 5. Savings with use of VSD on kitchen hoods .............................................................................................. 63
Figure 6. Screen shot of water saving measures for hotels in EDGE...................................................................... 83
Figure 7. Screen shot of materials saving measures for hotels in EDGE .............................................................. 105
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TABLE OF CONTENTS
LIST OF TABLES
Table 1: Base Case System Type Selection ............................................................................................................ 12
Table 2: Base Case System Description ................................................................................................................. 12
Table 3: Shading factors for horizontal shading devices at different locations..................................................... 20
Table 4: Shading factors for vertical shading devices at different locations. ........................................................ 21
Table 5: Shading factors for combined shading devices (both horizontal and vertical) at different locations. .... 21
Table 6: Typical shading devices............................................................................................................................ 22
Table 7: Shading strategies for different orientations at the design stage. .......................................................... 22
Table 8: Insulation types and typical conductivity range ...................................................................................... 25
Table 9: Thickness of insulation required to achieve a U Value of 0.45 W/m² K .................................................. 25
Table 10: Insulation types and typical conductivity range .................................................................................... 28
Table 11: Thickness of insulation required to achieve a U Value of 0.45 W/m² K ................................................ 28
Table 12: Approximate SHGC and U Values for different glazing types ................................................................ 31
Table 13: Approximate SHGC and U Values for different glazing types. ............................................................... 33
Table 14: Type of cross ventilation ........................................................................................................................ 34
Table 15: Depth of floor to ceiling height ratio for different room configurations ............................................... 35
Table 16: Total area of opening as a proportion of floor area for different heat gain ranges. ............................. 36
Table 17: Type of cross ventilation ........................................................................................................................ 37
Table 18: Depth of floor to ceiling height ratio for different room configurations ............................................... 38
Table 19: Total area of opening as a proportion of floor area for hotel guest rooms .......................................... 38
Table 20: Typical COPs for different types of air conditioning systems. ............................................................... 40
Table 21: Typical COPs for different types of air conditioning systems ................................................................ 42
Table 22: Types of Ground Source Heat Pumps. ................................................................................................... 46
Table 23: Recovery technology options ................................................................................................................ 52
Table 24: Benefits and limitations of the VSDs for pumps .................................................................................... 55
Table 25: Types of Condensing Boiler ................................................................................................................... 59
Table 26: Types of High Efficiency Hot Water Boilers ........................................................................................... 61
Table 27: Grey Water Heat Recovery Solutions .................................................................................................... 66
Table 28: Description of technologies (lamp types) .............................................................................................. 70
Table 29: Typical range of efficacies for different lamp types .............................................................................. 71
Table 30: Potential savings when using CFL lighting instead of incandescent bulbs Error! Bookmark not defined.
Table 31: Assumed lighting loads for the base case and improved case .............................................................. 71
Table 32: Description of technologies (lamp types) .............................................................................................. 72
Table 33: Assumed lighting loads for the base case and improved case. ............................................................. 73
Table 34: Description of technologies (lamp types) .............................................................................................. 74
Table 35: Assumed lighting loads for the base case and improved case .............................................................. 75
Table 36: Types of controls for lighting ................................................................................................................. 76
Table 37: Types of occupancy controls for bathrooms ......................................................................................... 78
Table 38: Types of occupancy controls for bathrooms ......................................................................................... 80
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ACRONYMS
ACRONYMS
AHU
Air Handling Unit
ARI
Air-conditioning and Refrigeration Institute
ASHRAE
American Society of Heating Refrigerating and Air-conditioning Engineers
Btu
British thermal unit
COP
Coefficient of Performance
EDGE
Excellence in Design for Greater Efficiencies
HVAC
Heating, Ventilation and Air-conditioning
kW
Kilowatt
kWh
Kilowatt-hour
SC
Shading Coefficient
SHGC
Solar Heat Gain Coefficient
sqm
Square Meter
STP
Sewage Treatment Plant
TR
Tonnage of Refrigeration
VLT
Visible Light Transmission
VAV
Variable Air Volume
VFD
Variable Frequency Drive
VSD
Variable Speed Drive
W
Watt
Wh
Watt-hour
WCF
Water Consumption Factor
WFR
Window to Floor Ratio
WWR
Window to Wall Ratio
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INTRODUCTION
INTRODUCTION
About EDGE (“Excellence in Design for Greater Efficiencies”)
EDGE is a building design tool, a certification system, and a global green standard for nearly 100 emerging
market countries. The platform is intended for anyone who is interested in the design of a green building,
whether an architect, engineer, developer, or building owner.
EDGE empowers the discovery of technical solutions at the early design stage to reduce operational expenses
and environmental impact. Based on the user’s information inputs and selection of green measures, EDGE
reveals projected operational savings and reduced carbon emissions. This overall picture of performance helps
to articulate a compelling business case for building green.
The EDGE software includes modules for homes, hotels, hospitals, offices, and retail, with building-specific user
guides accompanying them. This guide is specifically for new hotels and resorts design and construction.
EDGE is an innovation of IFC, a member of the World Bank Group.
A Global Green Standard
EDGE offers a set of technical measures that when selected will reduce a building’s operational and embodied
energy1 and water use. Only a handful of measures are required for better building performance that result in
lower utility costs, extended equipment service life, and less pressure on natural resources. To comply with the
EDGE standard a building must achieve a 20% reduction in all three areas when compared to a local
benchmark.
Depending on a user’s design inputs together with information on typical local practice and available building
codes, EDGE develops a building’s base case for energy and water use and the impact of embodied energy in
materials. A spectrum of localized data supports the base case for the project, ranging from a location’s
temperature profiles, rainfall patterns, and levels of solar radiation, to the building’s actual dimensions and the
economic strata of the occupants.
EDGE defines a global standard while contextualizing the base case to the occupants and their location.
The EDGE Perspective
Rather than relying on complex simulation software and consultants to predict resource use, EDGE has an easyto-use interface that hides a powerful building physics engine with region-specific data. Through user inputs,
the data can be further refined to create a highly nuanced set of calculations that have greater accuracy when
predicting future building performance. EDGE focuses intently on resource efficiency and climate change
mitigation, recognizing that too wide of a focus leads to disparate results.
The intention of EDGE is to democratize the green buildings market, which was previously reserved for higherend buildings standing in relative isolation in primarily industrialized nations. Government regulations in
emerging economies rarely require resource-efficient building practices. EDGE aims to create a new path for
green growth by proving the financial case in a practical, action-oriented way that emphasizes a quantitative
approach. Only then can the gap be closed between non-existent or weakly-enforced green building regulations
and expensive international standards, and the potential will be realized to lower utility costs while dramatically
reducing GHG emissions.
EDGE Methodology
At the heart of EDGE is a performance calculation engine that harnesses a set of mathematical equations based
on the principles of climatology, heat transfer, and building physics. Upon receiving design inputs, the calculator
charts a building’s potential performance in the areas of energy, water, and materials. As markets mature, the
underlying data in the calculator can be further sharpened, ensuring EDGE becomes more granular and up-todate.
Energy consumption is predicted using a quasi-steady state model (refer to the EDGE Methodology). The quasisteady state calculation methodology is based on the European CEN standards and ISO 13790. A similar
approach has been taken by energy efficacy building codes (e.g., COMcheck in the US, Simplified Building
Energy Model (SBEM) and SAP in the UK) and Energy Performance Certificates (EPCs in the EU) to find a quick
1
Embodied energy is the energy required to extract and manufacture the materials required to construct and maintain the
building.
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INTRODUCTION
and cost-effective way to benchmark buildings and to quantify carbon emission reductions. In the future,
accredited dynamic simulation models will also be an acceptable means of demonstrating compliance with the
EDGE standard.
To determine the base case parameters for efficiency in each of the required areas, EDGE relies on information
on typical building practices and national building performance codes, where they are in existence. For example,
if there is an energy efficiency code (EEC) in practice in a certain country, such as China or South Africa, then it
is used to support the base case calculation. Typical systems efficiencies for heating, ventilation, and air
conditioning systems have been based on the ASHRAE-90.1-2007 standard.
Rather than suggesting a perfect or prescribed scenario, EDGE provides users with a set of best-practice options
to explore in order to identify an optimum design solution. In this way, the user determines which bundle of
technical measures is the best choice for reaching required efficiency levels.
The purpose of EDGE is to produce consistent and reliable evaluations of resource demand for building
certification purposes. While EDGE may assist the design process, it is first and foremost a financial model and
should not be used for making strategic design decisions. If the performance of a particular feature is critical to
the design, it is prudent to use an appropriate modelling tool. In any case, EDGE should not be used for system
sizing or financial modeling.
EDGE Certification
Rather than a subjective, points-based merit system with weighted credit scores, EDGE certification is awarded
if efficiencies are achieved, resulting in tangible resource savings. A simple pass/fail system indicates whether
or not the building project has demonstrated the minimum 20% savings in operational energy, water, and
embodied energy of materials compared to the base case model. There are no tiers of achievement as
certification is driven by a simple set of metrics.
Requirements for EDGE compliance, at both the design and post-construction phases, are specified throughout
this guide, and include such deliverables as design drawings, manufacturers’ data sheets, calculations, proof of
delivery, and photographs. Assessment is provided by EDGE partners such as the World Green Building
Council’s network of affiliates in 96 countries and other international experts who serve as third-party,
accredited auditors. A design check is required for pre-certification and a site audit is required for final
certification.
EDGE certification makes a branding statement of corporate responsibility and environmental excellence.
Certification is currently being implemented on a country-by-country basis. To find out if EDGE is available in
your region, contact [email protected]
EDGE Hotels (Version 1.0) is optimized for the following:

Browser: Internet Explorer 8 or higher, or a recent version of Firefox, Chrome, or Safari

Operating System: Windows XP or higher, or Mac OS

Screen Resolution: Viewed best at 1600 X 900 pixels

Limited functionality is available on iPhones, Androids, and tablets
An Innovation of IFC
EDGE is an innovation of IFC, a member of the World Bank Group.
IFC
2121 Pennsylvania Avenue, NW
Washington, DC 20433
[email protected]
www.ifc.org/edge
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DESIGN PAGE GUIDANCE
DESIGN PAGE GUIDANCE
Information details must first be entered into the Design section in order to build the base case for the building.
Project Details
This section should be completed if you intend to submit your project for audit and certification.

Project Owner Name – Enter the name of the key contact from the company/organization that
commissioned the EDGE assessment.

Project Name – Enter the name of the development.

Hotel Name – Enter the name of the hotel or block that the assessment covers.

Project Owner Email – Enter the email address of the key contact from the company/organization that
commissioned the EDGE assessment.

Project Owner Phone – Enter the phone number of the key contact from the company/organization that
commissioned the EDGE assessment.

Project Address – Enter the full address of the development.
Location & Climate Data

Country – Select the country in which the project is located.

City – Select the city in which the project is located. If the building is in a city which is not included in
the list then please select the city that is located closest. If necessary, fine-tune the Key Assumptions
under “Monthly Average Outdoor Temperature (deg.C)” by over-riding the defaults.

Climate Type – EDGE uses the climate type to calculate the level of solar radiation. Select the climate
type for the region in which the building is located.
Basic Parameters




Star Rating of the Hotel – Select the rating of the hotel
Type of Hotel – Enter the specific type or category of the hotel, which are divided in two main due to
the site configuration, hotel and resorts.
Average Occupancy Rate – Enter the average percentage of rooms within the hotel that are occupied
by guests.
Select the type of amenities and services that the hotel provides.
Building Data

Floors Above Ground – Enter the total amount of floors above the ground level.

Floors Below Ground – Enter the total amount of floors below the ground level.

Total Guest Rooms – Enter the total amount of guest rooms in the hotel or resort.
Area Details

Guest Rooms (m²) – A default value is provided based on the selected number of guests. If the actual
area differs from the default, then enter it here.

Front of House (m²) – A default value is provided based on the selected number of guests. If the actual
area differs from the default, then enter it here.

Corridors (m²) – A default value is provided based on the selected number of guests. If the actual area
differs from the default, then enter it here.

Conference/Banquet (m²) – A default value is provided based on the selected number of guests. If the
actual area differs from the default, then enter it here.

Back of House (m²) – A default value is provided based on the selected number of guests. If the actual
area differs from the default, then enter it here.
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DESIGN PAGE GUIDANCE
Building Systems
The information in this section is used to calculate the improved case performance for the project building.

Air Conditioning – Select Yes or No. When “No” is selected, if EDGE predicts that the building is likely to
overheat, then the cooling load will be reflected as “virtual” energy. “Virtual” energy has the same
value as actual energy in EDGE so it must be reduced in the same way that actual energy is reduced.
“Virtual” energy usage appears in the chart on the energy page, and is indicated because EDGE
assumes that eventually mechanical systems will be added to the building (in the form of individual air
conditioning units, for example) to compensate for a lack of a building-wide cooling system.

Space Heating – Select Yes or No. When “No” is selected, if EDGE predicts that the building is likely to
require heating, then the heating load will be reflected as “virtual” energy.
Key Assumptions for the Base Case
The default values are used to calculate the base case performance of a building. If any of the values are
overwritten, justification must be provided in the form of supporting documentation, including a link to any
relevant local standards. It should be noted that some cells for baseline definition are locked for users and only
be available to the admin users to adjust.

Fuel Used for Electric Generator – The default fuel used for the electric generator appears for the
selected country.

Fuel Used for Hot Water Generation – The default fuel used for hot water generation appears for the
selected country.

Fuel Used for Cooking – The default fuel used for cooking appears for the selected country.

Fuel Used for Space Heating – The default fuel used for space heating appears for the selected country.

Diesel Percentage Used for Power Generation – The default percentage of diesel used for power
generation appears for the selected country.

Cost of Electricity – The default cost for electricity appears for the selected country.

Cost of Diesel Fuel – The default cost for diesel fuel appears for the selected country.

Cost of Natural Gas – The default cost for natural gas appears for the selected country.

Cost of Water – The default cost for water appears for the selected country.

Latitude – The latitude for the selected city is provided by default. If the building is outside of the
selected city, then the actual latitude of the site can be entered here.

CO2 Emissions from Electricity Generation g/kWh – A default emissions value appears for the selected
country.

Window to Wall Ratio – If a specific window to wall ratio is encouraged or required by local codes, enter
the percentage here. Note that the window to wall ratio in the Key Assumptions reflects local building
regulations or typical practice in the selected city.

Roof U Value – If local standards or regulations stipulate a maximum U Value for the roof and it differs
from the default value provided then it must be entered here.

Wall U Value – If local standards or regulations stipulate a maximum U Value for the walls and it differs
from the default value provided then it must be entered here.

Glass U Value – If local standards or Regulations stipulate a maximum U Value for the windows and it
differs from the default value provided then it must be entered here.

Glass SHGC – If local standards or regulations stipulate a maximum Solar Heat Gain Coefficient
(SHGC) for the glazing and it differs from the default value provided then it must be entered here.

Average Annual Rainfall – The average annual rainfall for the selected city is provided by default. If the
building is outside of the selected city, then the actual average annual rainfall of the site can be
entered here.

Cooling System – A default cooling system based on the ASHRAE methodology appears for the selected
building size, this cooling system sets the AC system efficiency of the next item. Table 2 describes the
cooling systems available in the ASHRAE methodology. If the cooling system differs from the default
value provided for the city, then it must be entered here.

AC System Efficiency – Change the COP value for air conditioning efficiency only if local standards
require a level of performance that differs from the default value provided. Otherwise, the AC System
efficiency is based on the following table:
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DESIGN PAGE GUIDANCE
Table 1: Base Case System Type Selection2
Building Type
1.
Fossil Fuel, Fossil/Electric
Hybrid, and Purchased Heat
Residential
2
Electric and
other
System 1 - PTAC
Constant Volume
2.
Nonresidential and 3 floors or less and <2300m
Packaged Terminal Heat Pump
Constant Volume
3.
Nonresidential and 4 or 5 floors and <2300m2
or 5 floors or less and 2,300m2 to 14,000m2
Packaged rooftop Air Conditioner
Constant Volume
4.
Nonresidential and more than 5 floors or
>14,000m2
Packaged rooftop Heat Pump
Constant Volume
Table 2: Base Case System Description 3
System No.
System Type
Fan Control
Cooling
Type
Heating Type
1.
PTAC
Packaged Terminal Air
Conditioner
Constant
Volume
Direct expansion
Hot water fossil fuel
boiler
2.
PTHP
Packaged Terminal Heat Pump
Constant
Volume
Direct expansion
Electric heat pump
3.
PSZ-AC
Packaged rooftop Air
Conditioner
Constant
Volume
Direct expansion
Fossil fuel furnace
4.
PSZ-HP
Packaged rooftop Heat Pump
Constant
Volume
Direct expansion
Electric heat pump
5.
Packaged VAV
with reheat
Packaged rooftop VAV with
reheat
VAV
Direct expansion
Hot water fossil fuel
boiler
6.
Packaged VAV
with PFP Boxes
Packaged rooftop VAV with
reheat
VAV
Direct expansion
Electric resistance
7.
VAV with reheat
Packaged rooftop VAV with
reheat
VAV
Chilled water
Hot water fossil fuel
boiler
8.
VAV with PFP
Boxes
VAV with reheat
VAV
Chilled water
Electric resistance

Heating System – A default heating system based on the ASHRAE methodology (Table 1 above)
appears for the selected building size, the type of system determines its efficiency included in ‘Heating
System Efficiency’. Table 2 describes the heating type equivalent to the cooling system as per ASHRAE
methodology. If the heating system differs from the default value provided for the city, then it must be
entered here.

Heating System Efficiency – Change the efficiency value for heating system only if local standards
require a level of performance that differs from the default value provided. Otherwise, the heating
System efficiency is based on the Table 1.

Monthly Average Outdoor Temperature (deg. C) – The monthly average outdoor temperature has only
been included for the cities listed for each country. If the project site is not within a listed city, then
enter the average monthly temperatures for the actual location. Additionally, for cities included in
EDGE, due to microclimates, it is understood that the monthly temperatures for the project site may
vary from the average temperatures for the city. For EDGE certification, the source for any
temperature inputs must be submitted for compliance purposes.
2
Source: ASHRAE 90.1 2007. Table G3.1.1A
3
Source: ASHRAE 90.1 2007. Table G3.1.1B
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GREEN MEASURES GUIDANCE
GREEN MEASURES GUIDANCE
EDGE Hotels include the following areas:

Results

Energy

Water

Materials
The content and purpose of each of these areas are described on the following pages, with instructions for
entering information in order to achieve best-case scenarios.
Results
The Results bar is a summary of the Key Performance Indicators (KPIs) calculated by EDGE. In order to
calculate performance against these indicators, EDGE makes assumptions on how the building will be used by
the occupants. Since the actual usage patterns may differ depending on occupant consumption, the water and
energy usage and subsequent costs may vary from EDGE predictions. The KPIs include:

Final Energy Use – the energy consumption (in kWh/month/unit) for the project is calculated
automatically by EDGE, based on the data entered in the Design section and any reduction
achieved through the selection of efficiency measures.

Final Water Use – the water consumption (in kL/month/unit) for the project is calculated
automatically by EDGE, based on the data entered in the Design section and any reduction
achieved through the selection of water efficiency measures.

Operational CO2 Savings – EDGE automatically calculates the CO2 savings (in tCO2/year) based on
the final energy use multiplied by the CO2 emission factor for the generation of grid electricity. The
default value for the selected country’s CO2 emissions is shown in the Design section, but can be
overwritten if evidence can be provided to support it.

Embodied Energy Savings – EDGE automatically calculates the embodied energy savings (in mega
joules) from the building dimensions and the materials selected in the Materials section.

Base Case Utility Costs – EDGE projects the monthly cost (in USD/month/unit or local currency in
specific countries) for energy and water use.

Utility Costs Reduction – EDGE projects the monthly savings (in USD/month/unit or local currency
in specific countries) in utility bills.

Incremental Cost – Additional cost of implementing the selected efficiency measures. (in USD or
local currency in specific countries)

Payback in Years – Number of years to repay the incremental cost compared to the cost of utilities.
Energy and Water
The selection of energy and water efficiency measures can have a significant impact on the resource demand of
a building. When measures are selected, EDGE makes default assumptions on the typical improved performance
over the base case. To the right of most measures, it is possible to over-write the default by adding more
specific values. If default values are edited, additional documentation is required for justification purposes.
While not technically efficiency measures, onsite renewable energy and the collection of rainwater will reduce
the use of grid electricity and treated potable water respectively, contributing to the 20% efficiency savings
target required to reach the EDGE standard.
EDGE currently uses delivered energy (i.e. that paid for by the consumer) as the measure of efficiency, as it is a
more consistent global indicator. The carbon dioxide emissions (global warming potential) related to delivered
energy use is a more accurate measure of the impact of a building on the environment, so future versions of
EDGE may consider using this alternative indicator.
The results for both Energy and Water are shown in graphs that compare the base case building with the
improved case. This graph displays a breakdown of the areas of consumption in the building, which some of
them are detailed as follows:
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GREEN MEASURES GUIDANCE
Energy Chart

Pumps: Only includes pumps dedicated to the HVAC system

Catering: Includes cooking equipment , refrigerator, kitchen equipment and extractor hoods

Laundry: This is the energy involved in washing and drying clothes.

Other: In the energy chart includes interior equipment, miscellaneous equipment, elevators, and
sewage treatment plant (STP), and water pumps.
Water Chart

Laundry: includes: cleaning the hotel building, washing clothes, and car washing.

Public Area: in the chart includes the water closets, urinals and faucets of the banquet hall, and
employees and public areas of the hotel.
Materials
A list of relevant specifications for each building element (roof, external walls, internal walls, floor finishes, etc.)
appears in the Materials section. For each building element a specification must be selected from the drop down
list that is most similar to the specification used in the design. Where there are multiple specifications for each
building element, the predominant specification should be selected. Thicknesses must be indicated for floor
slabs, roof construction, external walls, and internal walls.
The indicator used to measure materials efficiency is the embodied energy of the specifications used. The
embodied energy of a product is the primary energy demand for its production. As with the energy efficiency
measures, future versions of EDGE may consider using carbon dioxide (global warming potential) as an
indicator of materials efficiency as this more closely reflects the impact of the building on the environment.
Saving a Project
Users may save their projects within the EDGE software to retrieve upon login. To create multiple versions of a
project with different combinations of measures, it is best to retain your inputs by downloading the data into
separate pdfs and saving the documents on your computer. In this way, you maintain one master project file
for your building within EDGE.
EDGE can be accessed via handheld devices such as iPhones, Androids, and tablets. Exercise caution when
accessing saved projects via handheld devices as EDGE automatically saves changes to projects every three
minutes.
If a user is not active on EDGE for 20 minutes, the system will log the user out and changes will be missed if
not saved.
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TECHNICAL GUIDANCE
TECHNICAL GUIDANCE
The Technical Guidance section of this user guide describes each measure included in EDGE, indicating why the
measure has been included, how it is assessed, and what assumptions have been made in order to calculate the
base case and improved case. The guidance for each EDGE measure contains the subsections described below:
Requirement Summary
A brief summary of the system or level of performance required before the measure can be claimed.
Intention
What the measure aims to achieve and why it is measured in the way that it is.
Approach/Methodologies
The different approaches, which can be used to assess the design, are provided with an explanation of the
calculations and terminology used.
Potential Technologies/Strategies
The possible solutions and technologies that might be considered by the design team in order to meet measure
requirements.
Relationship to Other Measures
EDGE predicts energy, water, and materials efficiency by taking a holistic view of the information that has been
provided about the building project. The strong relationship between certain measures is revealed in order to
clarify EDGE calculations and support the overall design process.
Assumptions
EDGE makes assumptions for a base case building. The base case is taken from either typical practice or
performance levels required by applicable local codes and standards. An assumption is also made for the
improved case, so that when a measure is selected the predicted performance of the building is improved. Often
it is possible to over-ride improved case assumptions with more accurate levels of predicted performance for the
actual building design. This allows improvements to be recognized if the assumed improved case level isn’t met
and calculates additional reductions if the design exceeds the improved case.
Compliance Guidance
The compliance guidance provided for each measure indicates the documentation that will be required to
demonstrate compliance, should the project owner be striving for EDGE certification. Specific documentation
varies according to the technology being assessed.
EDGE provides compliance guidance for each measure at both the design and post-construction stages, as
available evidence depends on the current stage in the process.
In general, auditors are allowed to use their judgment if minor non-compliance issues arise. In most cases a
minimum of 90% of a particular specification must comply for certification, unless specifically stated.
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TECHNICAL GUIDANCE
Project Team
The project team must demonstrate that the specification meets the minimum performance required for the
improved case by providing the following:

A brief explanation of the relevant system or product specified/installed.

Calculations that have been used to assess and demonstrate compliance.

Manufacturer’s data sheets with information required to demonstrate compliance clearly
highlighted.

Proof that the specified system or product has been installed.
Auditor
The auditor verifies that the design/construction team has interpreted the requirements correctly and that all
compliance requirements have been fulfilled. The supporting evidence provided is reviewed to ensure it matches
the data used in the assessment.
Photographs used as evidence must be taken by the auditor during the site visit with a date stamp.
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ENERGY EFFICIENCY MEASURES
ENERGY EFFICIENCY MEASURES
Energy efficiency is one of the three main resource categories that comprise the EDGE standard. In order to
comply for certification purposes, the design and construction team must review the requirements for selected
measures as indicated and provide the information.
The following pages explain each energy efficiency measure by relaying the intention, approach, assumptions,
and compliance guidance requirements.
Figure 1. Screenshot of energy saving measures for hotels in EDGE
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ENERGY EFFICIENCY MEASURES
HTE01 – REDUCED WINDOW TO WALL RATIO
Requirement Summary
This measure can be claimed if the Window to Wall Ratio is lower than the local base case as set out in the Key
Assumptions for the Base Case in the Design section. EDGE will calculate the impact of any improvement
beyond the base case.
Intention
Finding the correct balance between the transparent (glass) and the opaque surfaces in the external façades
helps to maximize daylight while minimizing unwanted heat transfer, resulting in reduced energy consumption.
This is because the sun is the most powerful light source but is also a source of significant heat gain. Therefore,
it is important to balance lighting and ventilation benefits of glazing against the impacts of heat gain on cooling
needs and/or passive heating. The design goal should be to meet minimum illumination levels without
significantly exceeding the solar heat gains in temperate and warm climates, as well as to make the most of
passive heating in cold climates in winter time.
Windows are usually the weakest link in the building envelope as the glass has much lower resistance to heat
flow than other building materials. Heat flows out through a glazed window more than 10 times faster than it
does through a well-insulated wall. While glazed areas are desirable to admit solar radiation in cold climates
during the day, windows in warmer climates can significantly increase the building’s cooling loads.
Approach/Methodologies
This measure uses the Window to Wall Ratio (WWR), which is the window or other glazing area (including
mullions and frames) divided by the gross exterior wall area, which includes opaque and transparent elements,
such as doors, windows, and walls from the outside. Windows generally transmit heat into the building at a
higher rate than walls do. As such, a building with a higher WWR will transfer more heat than a building with a
lesser WWR.
The WWR is calculated with the following equation:
WWR (%) =
∑ Glazing area (m2 )
∑ Gross exterior wall area (m2 )
Glazing area is the area of glass on all façades regardless of orientation. Gross exterior wall area is also the sum
of the area of the façade in all orientations.
Any external wall that is not exposed to the environment directly (e.g. Underground or earth-bermed walls,
walls that in direct contact with walls of another building) should not be included in the WWR calculations.
Spandrel panels, which are opaque insulated glass panels, should be counted as wall in the WWR calculations.
Potential Technologies/Strategies
If the WWR is higher than the default value, then other measures such as shading or the lower solar heat gain
coefficient (SHGC) of the glass should be considered to offset the energy loss due to cooling when increasing
the WWR. In cold climates, when the WWR is higher than the default, the insulation of glass using double or
triple glazing should be considered.
With regards to daylight, there are two basic strategies for using the sun for lighting while minimizing heat gain.
The first is to use a small window opening (15% WWR) to illuminate a surface inside the space that then
spreads the light out over a large area. The second is to use a moderately sized window (30% WWR) that
“sees” an exterior reflective surface but is shaded from the direct sun. To increase the daylight availability, the
selection of higher visual light transmittance (VLT>50) for the glass is also important.
Relationship to Other Measures
Envelope transfer is a function of the thermal resistance of the external materials, the area of the building
façade, and the temperature difference between the exterior and interior of the building. The primary causes of
heat transfer are infiltration and windows. The size, number, and orientation of windows greatly affect the
building’s energy use for thermal comfort purposes (heating or cooling). In cold climates, direct solar radiation
passes through the glass during the day, passively heating the interior. If the correct thermal mass is used, this
heat is then released, helping to keep the room comfortable later in the day. It is desirable that in this climate
type the glass is placed in the elevation with the greatest exposure to sunlight. However, in warm and
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ENERGY EFFICIENCY MEASURES
temperate climates, the WWR tends to be lower as the reduction of glass leads to a reduction in the overall
cooling load, as the need for air conditioning is reduced.
Although EDGE is unable to estimate the effect of daylight within the energy consumption, it is important to
consider that lighting and cooling energy portions can be reduced due to the use of daylighting, which should be
balanced with the solar heat gains and the convective heat gains.
Assumptions
The base cases for the WWR are included in the Key Assumptions for the Base Case in the Design section. The
improved case assumptions for the WWR may vary from country to country as well as per hotel type. It is also
possible to enter the desired WWR value for the improved case manually. If the design has higher WWR than
base case, the actual WWR should be entered to the system, this may have negative impact on energy saving,
however it should be compensated by other saving measures.
Compliance Guidance
At the post-construction stage it is important to ensure that the WWR has been maintained in order to achieve
the energy savings indicated in the EDGE results. Compliance is achieved when the design team can
demonstrate that the WWR in all elevations is equal or lower than the claimed specification, using the formula
explained in “Potential Technologies/Strategies” above.
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Calculation of “Glazing Area” and “Gross Exterior
Wall Area” for each façade of the building and the
average building area weighted WWR.
All façade elevation drawings showing glazing
dimensions and general building dimensions.
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


As-built façade drawings. External and internal
photographs of the building showing all the
elevations.
Updated WWR calculations if required, or
confirmation that the design WWR is still valid.
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ENERGY EFFICIENCY MEASURES
HTE02 – EXTERNAL SHADING DEVICES
Requirement Summary
This measure can be claimed if external shading devices are
provided on the building’s exterior. As a default, EDGE uses a
shading factor equivalent to that of a shading device that is 1/3
of the height of the window and 1/3 of the width of the window
on all windows of the building. However, if shading devices are
provided that are different from EDGE assumptions then
logically a different shading factor can be used. The shading
factor varies according to the latitude and the orientation of the
windows, as well as the size of the shading device.
Intention
External shading devices are designed on the building façade in
order to protect the glazing elements (windows) from direct
solar radiation, as once solar radiation has penetrated the
glass, it becomes trapped, increasing both solar heat gain and
glare.
Figure 2. Relation between the Dh and Dv
(depth of horizontal and vertical shading) H
(window height) and W (window width) is
given in tables 4, 5 and 6 to define the shading
requirements
Approach/Methodologies
This measure is assessed using a shading factor, which is one minus the ratio of solar radiation transmitted by a
protected window (with external shading devices), compared to that transmitted by an unprotected window.
The shading factor is expressed as a decimal value between 0 and 1. The higher the shading factor, the greater
is the shading capability from the shading device. Table 3, Table 4 and Table 5 indicate the shading factors for
different orientations, latitudes, and shading device proportions. The last column of Table 5 lists the average
shading factor for the combined type, which is used as the default improved case by EDGE.
Table 3: Shading factors for horizontal shading devices at different locations.
*The shading factors have been derived using a solar modelling tool, and are an average of all eight orientations.
HORIZONTAL - SHADING FACTOR* (Shading Coefficient)
N (North), NE (North East), E (East), SE (South East), S (South), SW (South West), W (West), NW (North West)
Shading
Latitude
Shading Factor
Proportion
Northern
Hemisphere
N
Southern
Hemisphere
S
SE
E
NE
N
NW
W
SW
Dh=H/1
0.49
0.46
0.49
0.50
0.50
0.52
0.52
0.48
0.50
Dh =H/2
Dh =H/3
Dh =H/4
Dh=H/1
Dh =H/2
Dh =H/3
Dh =H/4
Dh=H/1
Dh =H/2
Dh =H/3
Dh =H/4
Dh=H/1
Dh =H/2
Dh =H/3
Dh =H/4
Dh=H/1
Dh =H/2
Dh =H/3
Dh =H/4
Dh=H/1
Dh =H/2
Dh =H/3
Dh =H/4
0.44
0.39
0.39
0.40
0.46
0.43
0.41
0.41
0.39
0.34
0.32
0.33
0.39
0.36
0.34
0.35
0.35
0.29
0.27
0.28
0.33
0.31
0.28
0.30
0.47
0.44
0.47
0.51
0.51
0.52
0.49
0.47
0.42
0.38
0.38
0.40
0.43
0.42
0.41
0.41
0.36
0.33
0.31
0.32
0.35
0.35
0.34
0.35
0.32
0.29
0.26
0.27
0.30
0.30
0.30
0.32
0.47
0.44
0.47
0.50
0.51
0.52
0.50
0.46
0.41
0.38
0.37
0.39
0.41
0.41
0.40
0.41
0.36
0.33
0.31
0.32
0.34
0.34
0.34
0.35
0.31
0.28
0.26
0.26
0.29
0.29
0.28
0.31
0.47
0.43
0.46
0.49
0.51
0.51
0.49
0.46
0.41
0.37
0.36
0.38
0.40
0.40
0.39
0.40
0.36
0.32
0.29
0.30
0.33
0.32
0.33
0.35
0.31
0.28
0.25
0.25
0.28
0.27
0.28
0.31
0.46
0.39
0.40
0.43
0.46
0.46
0.45
0.44
0.40
0.34
0.31
0.33
0.36
0.36
0.37
0.39
0.35
0.29
0.25
0.26
0.29
0.29
0.30
0.33
0.31
0.25
0.21
0.21
0.23
0.24
0.26
0.29
0.33
0.30
0.34
0.38
0.40
0.39
0.36
0.32
0.24
0.23
0.24
0.26
0.28
0.26
0.25
0.24
0.18
0.18
0.18
0.19
0.20
0.19
0.19
0.19
0.15
0.14
0.14
0.15
0.16
0.15
0.15
0.15
0.42
0.35
0.30
0.48
0.40
0.34
0.29
0.48
0.40
0.33
0.29
0.48
0.39
0.32
0.28
0.44
0.36
0.30
0.25
0.35
0.25
0.19
0.15
0º - 9º
10º - 19º
20º - 29º
30º - 39º
40º - 49º
50º - 60º
NE
E
SE
S
SW
W
NW
Average
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ENERGY EFFICIENCY MEASURES
Table 4: Shading factors for vertical shading devices at different locations.
VERTICAL - SHADING FACTOR* (Shading Coefficient)
N (North), NE (North East), E (East), SE (South East), S (South), SW (South West), W (West), NW (North West)
Shading
Latitude
Shading Factor
Proportion
Northern
Hemisphere
N
NE
E
SE
S
SW
W
NW
Southern
Hemisphere
S
SE
E
NE
N
NW
W
SW
0.23
0.23
0.18
0.22
0.23
0.20
0.18
0.21
0.21
0.19
0.15
0.18
0.22
0.17
0.15
0.18
0.19
0.16
0.12
0.15
0.19
0.14
0.12
0.15
0.16
0.14
0.11
0.12
0.16
0.12
0.11
0.13
0.21
0.24
0.20
0.20
0.23
0.18
0.20
0.21
0.19
0.21
0.16
0.16
0.21
0.15
0.17
0.19
0.17
0.18
0.14
0.13
0.17
0.14
0.15
0.16
0.15
0.16
0.12
0.11
0.15
0.12
0.13
0.15
0.22
0.25
0.20
0.21
0.24
0.19
0.20
0.22
0.19
0.21
0.16
0.17
0.20
0.16
0.17
0.19
0.17
0.18
0.13
0.14
0.17
0.14
0.14
0.17
0.15
0.15
0.12
0.11
0.14
0.12
0.12
0.15
0.21
0.26
0.22
0.21
0.24
0.19
0.21
0.23
0.19
0.22
0.17
0.16
0.19
0.16
0.18
0.20
0.17
0.19
0.14
0.13
0.16
0.14
0.15
0.17
0.15
0.16
0.12
0.11
0.14
0.11
0.13
0.15
0.23
0.28
0.24
0.24
0.25
0.23
0.22
0.24
0.20
0.23
0.19
0.17
0.20
0.18
0.19
0.21
0.18
0.19
0.15
0.14
0.16
0.15
0.16
0.17
0.16
0.16
0.13
0.11
0.14
0.13
0.14
0.15
0.26
0.30
0.27
0.27
0.27
0.26
0.27
0.28
0.20
0.22
0.20
0.18
0.20
0.19
0.21
0.21
0.16
0.17
0.16
0.14
0.15
0.15
0.16
0.16
0.13
0.14
0.13
0.11
0.12
0.12
0.13
0.13
0º - 9º
10º - 19º
20º - 29º
30º - 39º
40º - 49º
50º - 60º
Average
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
0.21
0.18
0.15
0.13
0.21
0.18
0.15
0.13
0.21
0.18
0.15
0.13
0.22
0.19
0.16
0.13
0.24
0.20
0.16
0.14
0.27
0.20
0.16
0.13
Table 5: Shading factors for combined shading devices (both horizontal and vertical) at different locations.
COMBINED - SHADING FACTOR (Shading Coefficient)
N (North), NE (North East), E (East), SE (South East), S (South), SW (South West), W (West), NW (North West)
Shading proportion
Latitude
Shading Factor
Northern
N
NE
E
SE
S
SW
W
NW
Hemisphere
Average
Southern
Hemisphere
0º - 9º
10º - 19º
20º - 29º
30º - 39º
40º - 49º
50º - 60º
Dh=H/1 &
Dh=H/2 &
Dh=H/3 &
Dh=H/4 &
Dh=H/1 &
Dh=H/2 &
Dh=H/3 &
Dh=H/4 &
Dh=H/1 &
Dh=H/2 &
Dh=H/3 &
Dh=H/4 &
Dh=H/1 &
Dh=H/2 &
Dh=H/3 &
Dh=H/4 &
Dh=H/1 &
Dh=H/2 &
Dh=H/3 &
Dh=H/4 &
Dh=H/1 &
Dh=H/2 &
Dh=H/3 &
Dh=H/4 &
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
Dv=W/1
Dv=W/2
Dv=W/3
Dv=W/4
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S
SE
E
NE
N
NW
W
SW
0.72
0.69
0.67
0.72
0.74
0.73
0.70
0.70
0.65
0.59
0.54
0.58
0.68
0.60
0.56
0.60
0.58
0.50
0.45
0.48
0.58
0.51
0.47
0.51
0.51
0.43
0.38
0.41
0.50
0.43
0.39
0.44
0.69
0.69
0.67
0.71
0.74
0.70
0.70
0.68
0.60
0.59
0.54
0.56
0.64
0.57
0.59
0.60
0.53
0.51
0.45
0.45
0.53
0.49
0.50
0.52
0.47
0.45
0.39
0.38
0.45
0.42
0.43
0.46
0.69
0.69
0.68
0.71
0.75
0.71
0.70
0.69
0.61
0.59
0.54
0.56
0.62
0.57
0.57
0.60
0.53
0.51
0.44
0.46
0.51
0.48
0.48
0.52
0.47
0.44
0.38
0.38
0.43
0.41
0.41
0.46
0.69
0.69
0.68
0.71
0.75
0.70
0.70
0.69
0.60
0.59
0.53
0.55
0.60
0.56
0.57
0.61
0.53
0.51
0.44
0.44
0.49
0.47
0.48
0.52
0.47
0.44
0.37
0.36
0.41
0.39
0.41
0.46
0.69
0.68
0.64
0.68
0.71
0.69
0.68
0.68
0.61
0.57
0.50
0.50
0.56
0.54
0.56
0.59
0.53
0.49
0.41
0.40
0.45
0.44
0.47
0.51
0.47
0.42
0.35
0.32
0.37
0.37
0.40
0.45
0.62
0.63
0.63
0.66
0.68
0.66
0.65
0.62
0.53
0.51
0.48
0.48
0.51
0.49
0.51
0.53
0.43
0.42
0.38
0.37
0.39
0.38
0.41
0.43
0.36
0.34
0.31
0.29
0.31
0.30
0.34
0.36
0.71
0.60
0.51
0.44
0.70
0.59
0.50
0.43
0.70
0.58
0.49
0.42
0.70
0.58
0.48
0.41
0.68
0.55
0.46
0.39
0.64
0.50
0.40
0.33
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ENERGY EFFICIENCY MEASURES
Potential Technologies/Strategies
There are three basic types of solar shading: horizontal, vertical, and combined (egg crate).
Table 6: Typical shading devices
Shading Type
Horizontal shading
devices
(overhangs):
Image
Description
These are useful for building façades where the sun’s
rays are at a high angle of incidence, in short, where the
sun appears high in the sky.
Examples include summer mid-day sun on either the
northern or southern façades of a building for higher
latitudes, or east and west façades for equatorial
latitudes.
These applications are useful where the sun’s rays are at
a low angle of incidence (where the sun appears low in
the sky).
Vertical shading
devices (fins):
Combined shading
devices(egg crate):
Moveable shading
devices – louvres or
shutters
Examples include eastern sun on eastern façades,
western sun on western façades, and winter sun on
southern or northern façades in high latitudes.
“Egg crate” devices are used for conditions where
different times of the year warrant different shading
needs.
These devices are used to control sunlight during the day
as well as reduce heat losses at night. They are moveable
and can be mechanical or manual. They often provide
maximum shading as they fully cover the window. A
shading factor with shutters can be 1 if the shutters are
fully closed.
These shading devices also protect from inclement
weather (hail, wind, or rain) as well as provide privacy
and security.
The effectiveness of a shading device varies depending on the location towards the equator (latitude) and the
orientation of the window. Table 6 gives an early indication of the appropriate type of shading device for each
orientation.
Table 7: Shading strategies for different orientations at the design stage.
ORIENTATION
Equator-facing
East
Pole-facing
West
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EFFECTIVE SHADING
Fixed Horizontal Device
Vertical Device/Louvres (moveable)
Not required
Vertical Device/Louvres (moveable)
22
ENERGY EFFICIENCY MEASURES
Example:
A hotel building in Metro Manila (Philippines) has vertical shading which is half of the window width on all
windows and all directions, what shading factor the user should enter to the EDGE tool?
Step one is to find out, what is the latitude of Metro Manila? By using to EDGE online tool and selecting the
country (Philippines) and city (Metro Manila) in design tab, under “Key Assumptions for the Base Case” answer
is 14.6.
Step two is to use provided table for Vertical shading (Table 4) and look for appropriate latitude which is “10o to
19o”, as the shading is half of the window width then “Dv=W/2” should be selected. The average shading factor
will be 0.18.
Step three is to input 0.18 in to the average annual shading factor (AASF) filed in the tool and select external
shading measure.
Relationship to Other Measures
External shading will reduce the heat gain through solar radiation, therefore a glazing with a higher solar heat
gain coefficient can be selected. As external shading can cut the solar heat before hitting the glazed element, it
offers better thermal comfort conditions due to a reduction in radiative heat compared to a treated glass
without shading.
As shading devices are designed to reduce heat gains, the efficiency of the cooling system will affect the
reduction that solar shading can achieve. The more efficient the cooling system the less the energy consumption
will be reduced due to external shading.
In addition, when external shading is incorporated, the heating consumption is increased due to the reduction of
solar heat gains. This mostly applies to countries with a higher heating load.
Assumptions
For the base case, EDGE assumes that there is no solar shading present.
For the improved case, EDGE assumes a shading factor equivalent to shading devices with a proportion of 1/3
of the height and the width of the window, which have been fitted to all windows. The shading factor is the
annual average of eight orientations as shown in the last column of Table 3, Table 4 and Table 5, which is a
combination of both vertical and horizontal solar shading.
Annual Average Shading Factor (AASF) is defined by following equation:
AASF = 1 −
Total annual solar heat gain from a window with shading (kWhr)
Total annual solar heat gain from a window without shading (kWhr)
Compliance Guidance
The information required to demonstrate compliance will depend on the design solution adopted. The simplest
design approach is egg crate shading devices (depth of 1/3 the height and the width) on all windows on all
façades. Design teams may prefer to specify the shading device according to the orientation. Table 3, Table 4, Table
5, Table 6 and Table 7 can be used as guidelines for different sizes and types of shading devices and orientation.
Compliance is demonstrated when the average of the shading factor of all orientations is equal to or lower than
the default improved specification. In case the building has a more complex shading design, the design team
can use specialized software to demonstrate that average shading factors have been achieved.
Design Stage
At the design stage one or all of the following must be
used to demonstrate compliance:



All façade elevation drawings highlighting the
provision of horizontal and vertical shading devices.
Window details clearly showing the depth of the
shading device and the calculation of the proportion.
If vertical and horizontal shading are not provided
on all windows, the design team will need to provide
the output from the solar shading design software.
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Post-Construction Stage
At the post-construction stage one or all of the
following must be used to demonstrate compliance:



Photographs of the shading devices on all façades.
As-built façade drawings showing the shading
devices that have been installed.
Update of shading factor calculations in case of
changes from the design stage.
23
ENERGY EFFICIENCY MEASURES
HTE03 – INSULATION OF ROOF SURFACES
Requirement Summary
This measure refers to the U Value or thermal conductivity of materials as the indicator of performance, in
which the use of insulation improves the U Value. The measure can be claimed if the U Value of the roof is lower
than the base case U Value listed in the Key Assumptions for the Base Case in the Design section.
Intention
Insulation is used to prevent heat transmission from the external environment to the internal space (for warm
climates) and from the internal space to the external environment (for cold climates). Insulation aids in the
reduction of heat transmission by conduction4, so more insulation implies a lower U Value and better
performance. A well-insulated building has lower cooling and/or heating energy requirements.
Approach/Methodologies
This measure uses U Value, which is defined as the quantity of heat that flows through a unit area in unit time,
per unit difference in temperature; it is expressed in Watts per square meter Kelvin (W/m²K). U Value is an
indication of how much thermal energy (heat) is transmitted through a material (thermal transmittance), but it
also includes losses due to convection and radiation. The U Value, which is the performance indicator of this
measure, is the reciprocal of the total thermal resistance5 (1/∑R) of the roof, which is calculated from the
individual thermal resistance of each component/layer of the roof.
If the default improved case is used, the design team must demonstrate that the U Value of the roof does not
exceed the U Value assumed by EDGE (see assumptions below). This can be obtained by the manufacturer or
by the “simple method” calculation, which is explained as follows. If a different U Value for the roof is used,
then it must be calculated with the following formula or in accordance with the “combined method”6 given in
ISO 6946.
Simple method of calculating the U Value:
Where:
𝑼 − 𝑽𝒂𝒍𝒖𝒆 =
𝟏
𝑹𝒔𝒊+𝑹𝒔𝒐+𝑹𝟏+𝑹𝟐+𝑹𝟑 𝒆𝒕𝒄
Rsi = Resistance of the air layer on the inner side of the roof (add constant of air)
Rso = Resistance of the air layer on the external side of the roof
R1,2 etc = Resistance of each material layer within the roof
The resistance of a roof material is derived by the following formula:
Where:
𝑹=
𝒅

d = Thickness of the layer of material (m)
 = Thermal conductivity7 in W/m K
As the calculation of the U Value can be quite complex, dedicated U Value calculation software or energy
modelling software can be used.
4
Conduction is the process by which thermal energy moves within an object or between connected objects.
Thermal resistance is a measure of how much heat loss is reduced through the given thickness of a material. Thermal
resistance is expressed as the R, which is measured in square meters Kelvin per Watt (m²K/W).
6
Several websites give worked examples for the calculation of the U Value according to the “combined method”:
1.
Conventions for U Value calculations, Brian Anderson, BRE, 2006.
http://www.bre.co.uk/filelibrary/pdf/rpts/BR_443_(2006_Edition).pdf
2.
Worked examples of U Value calculations using the combined method, The Scottish Government, 2009 http://www.scotland.gov.uk/Resource/Doc/217736/0088293.pdf
3.
Determining U Values for real building elements, CIBSE - http://www.cibsejournal.com/cpd/2011-06/
7
Thermal conductivity is a standardized measure of how easily heat flows through any specific material, independent of
material thickness. It is measured in Watts per meter Kelvin (W/m K), and is often expressed as the “K Value” or “”.
5
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ENERGY EFFICIENCY MEASURES
Potential Technologies/Strategies
Insulating the roof is potentially the most cost-effective way to reduce the energy used for heating a building.
Therefore in cold or temperate climates there is a strong case for maximizing the insulation before designing the
heating ventilation and air conditioning equipment. In hot climates insulating the roof can reduce heat gain, but
the effect is relatively minor.
There are different types of insulation available and the appropriate type will depend on the application as well
as cost and availability. Insulation types can be grouped into four main categories, as shown in the following
table:
Table 8: Insulation types and typical conductivity range
Insulation Type
Description
Typical
Conductivity
Range
( - K Value)
Matting, Blanket,
or Quilt Insulation
This type of insulation is sold in rolls of different thicknesses and is typically
made from mineral wool (fiber made from glass or rock). Some common uses
include insulating empty lofts, stud walls, and under suspended timber floors.
Other materials such as sheep’s wool are also available.
0.034 – 0.044
Loose-fill Material
Loose-fill material, made of cork granules, vermiculite, mineral wool, or
cellulose fiber is usually poured between the joists to insulate lofts. It is ideal for
loft spaces with awkward corners or obstructions, or if the joists are irregularly
spaced.
0.035 – 0.055
Blown Insulation
This is made from cellulose fibers or mineral wool. Spray foam insulation is
made from Polyurethane (PUR). Blown insulation should only be installed by
professionals, who use special equipment to blow the material into a specific,
sectioned-off area, to the required depth. The material may remain loose if used
for loft insulation, but can also bond to a surface (and itself) for insulating stud
walls and other spaces.
0.023 – 0.046
Rigid Insulation
Boards
They are mostly made from foamed plastic such as polystyrene, polyurethane
(PUR), or polyisocyanurate (PIR), which can be used to insulate walls, floors,
and ceilings. PUR and PIR board are among the best insulation materials
commonly used, and so are useful where space is limited. Rigid board has to be
cut to size, so fitting is often a skilled job.
0.02 – 0.081
Measure HTE05 assumes an improved roof U Value, which varies upon location. Table 9 demonstrates how to
achieve a U Value of 0.45W/m² K, with the thickness of certain insulation materials indicated. The actual
thickness required will depend on many other factors, including the fixing method, roof construction, and
position of the insulation within the material layers.
Table 9: Thickness of insulation required to achieve a U Value of 0.45 W/m² K
Thickness (mm)
Insulation Type
Approximate values to achieve a U Value
of 0.45W/m2 K
Vacuum Insulated Panels
10 - 20mm
Polyurethane (PU)
40 - 80mm
Polyisocyanurate (PIR)
40 - 60mm
Phenolic Foam (PF)
40 - 55mm
Expanded Polystyrene
60 - 95mm
Extruded Polystyrene
Wool and Fiber
50 - 80mm
60 - 130mm
Source: Insulation Materials Chart, Energy Savings Trust, 2004.
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
Selecting this measure will show an increase in the environmental impact in the materials section due to the
addition of insulation material (reflected as a negative percent improvement).
However, by increasing the level of insulation the heating and/or cooling loads will be reduced. Increasing the
levels of insulation could therefore reduce the cost and environmental impact of the heating and cooling plant,
leading to energy savings that more than compensate for the negative impacts in the materials section.
Assumptions
The insulation fitted in the roof for the base case varies by location, which is revealed in the U Value shown in
the Key Assumptions for the Base Case in the Design section. The improved case assumes that the actual U
Value will be better (lower) than the base case as listed in the Key Assumptions.
Compliance Guidance
In order to claim this measure, it is necessary to demonstrate that the U Value of the complete roof
specification is better (lower) than the base case as listed in the Key Assumptions for the Base Case in the
Design section. If the improved case U Value is used then it is only necessary to demonstrate that insulation has
been or will be installed, and that the reciprocal of the sum of the R Values for each component of the roof
structure does not exceed the base case.
If a U Value has been entered that exceeds the improved case then it will be necessary to confirm that the U
Value was calculated in accordance with the “combined method” given in ISO 6946.
If U Value of roof is worse (higher) than base case, it is necessary to enter the higher U value and
select the insulation of the roof under energy tab HTE03.
Design Stage
At the design stage the following evidence must be
used to demonstrate compliance:



A roof construction detail drawing showing the
insulation material. Ideally the roof detail drawing
should be annotated with the U Value of the roof.
Calculations of U value either using the formula or
U value calculators.
Manufacturer’s data sheet of specified insulation
material for the roof.
Post-Construction Stage
Since at the post-construction stage the insulation
material will not be visible, it must be demonstrated
that the insulation material specified at the design
stage was delivered to the site. The following must be
used to demonstrate compliance:



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Delivery note confirming that the insulation
material was delivered to the site.
Photographs of the roof construction at a point
when the insulation material was visible.
Updated calculations for the U value if the
thickness and type of insulation changed from the
original design.
26
ENERGY EFFICIENCY MEASURES
HTE04 – INSULATION OF EXTERNAL WALLS
Requirement Summary
This measure refers to U Value as the indicator of performance, in which the use of insulation improves the U
Value. The measure can be claimed if the U Value of the external walls is lower than the base case U Value
listed in the Key Assumptions for the Base Case in the Design section.
Intention
Insulation is used to prevent heat transmission from the external environment to the internal space (for warm
climates) and from the internal space to the external environment (for cold climates). Insulation aids in the
reduction of heat transmission by conduction8, so more insulation implies a lower U Value and better
performance. A well-insulated building has lower cooling and/or heating energy requirements.
Approach/Methodologies
This measure uses U Value, which is defined as the quantity of heat that flows through unit area in unit time,
per unit difference in temperature; it is expressed in Watts per square meter Kelvin (W/m²K). U Value is an
indication of how much thermal energy (heat) is transmitted through a material (thermal transmittance), but it
also includes losses due to convection and radiation. The U Value, which is the performance indicator of this
measure, is the reciprocal of the total thermal resistance9 (1/∑R) of the external walls, which is calculated from
the individual thermal resistance of each component/layer of each external wall.
If the default improved case is used (as shown in EDGE as the top insulation material in the dropdown), the
design team must demonstrate that the U Value of the external walls does not exceed the U Value assumed by
EDGE. This can be obtained by the manufacturer or by the “simple method” calculation, which is explained as
follows. If a different U Value for the external walls is used, then it must be calculated with the following
formula or in accordance with the “combined method”10 given in ISO 6946.
Simple method of calculating the U Value:
Where:
𝑼 − 𝑽𝒂𝒍𝒖𝒆 =
𝟏
𝑹𝒔𝒊+𝑹𝒔𝒐+𝑹𝟏+𝑹𝟐+𝑹𝟑 𝒆𝒕𝒄
Rsi = Resistance of air layer on the inner side of the external wall (add constant of air)
Rso = Resistance of air layer on the external side of the external wall
R1, 2 etc = Resistance of each layer material within the external wall
The resistance of a wall material is derived by the following formula:
Where:
𝑹=
𝒅

d = Thickness of the layer of material (m)
 = Thermal conductivity11 in W/m K
As the calculation of the U Value can be quite complex, dedicated U Value calculation software or energy
modelling software can be used.
8
Conduction is the process by which thermal energy moves within an object or between connected objects.
Thermal resistance is a measure of how much heat loss is reduced through a given thickness of a material. Thermal resistance
is expressed as the R, which is measured in square meters Kelvin per Watt (m²K/W).
10
Several websites give worked examples for the calculation of the U Value according to the “combined method”:
4.
Conventions for U Value calculations, Brian Anderson, BRE, 2006.
http://www.bre.co.uk/filelibrary/pdf/rpts/BR_443_(2006_Edition).pdf
5.
Worked examples of U Value calculations using the combined method, The Scottish Government, 2009 http://www.scotland.gov.uk/Resource/Doc/217736/0088293.pdf
6.
Determining U Values for real building elements, CIBSE - http://www.cibsejournal.com/cpd/2011-06/
11
Thermal conductivity is a standardized measure of how easily heat flows through any specific material, independent of
material thickness. It is measured in Watts per meter Kelvin (W/m K), and is often expressed as the “K Value” or “”.
9
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ENERGY EFFICIENCY MEASURES
Potential Technologies/Strategies
Insulating the external walls is potentially the most cost-effective way to reduce the energy used for heating a
building. Therefore in cold or temperate climates there is a strong case for maximizing the insulation before
designing the heating ventilation and air conditioning equipment. In hot climates insulating the wall can reduce
heat gain, but the effect is relatively minor.
There are different types of insulation available and the appropriate type will depend on the application as well
as cost and availability. Insulation types can be grouped into four main categories, as shown in the following
table:
Table 10: Insulation types and typical conductivity range 12
Insulation
Type
Matting, Blanket,
or Quilt
Insulation
Loose-fill
Material
Description
Typical
Conductivity
Range
( - K Value)
This type of insulation is sold in rolls of different thicknesses and is typically made
from mineral wool (fiber made from glass or rock). Some common uses include
insulating stud walls and under suspended timber floors. Other materials such as
sheep’s wool are also available.
0.034 – 0.061
Loose-fill material, made of cork granules, vermiculite, mineral wool, or cellulose
fiber, is usually poured between the joists to insulate lofts. It is ideal for cavity
walls, or if the joists are irregularly spaced.
0.038 – 0.067
Blown Insulation
This is made from cellulose fibers or mineral wool. Spray foam insulation is made
from Polyurethane (PUR). Blown insulation should only be installed by
professionals, who use special equipment to blow the material into a specific,
sectioned-off area, to the required depth. The material may remain loose if used
for cavity wall, but can also bond to a surface (and itself) for insulating stud walls
and other spaces.
Rigid Insulation
Boards
They are mostly made from foamed plastic such as polystyrene, polyurethane
(PUR), or polyisocyanurate (PIR), which can be used to insulate walls, floors, and
ceilings. PUR and PIR board are among the best insulation materials commonly
used, and so are useful where space is limited. Rigid board has to be cut to size,
so fitting is often a skilled job.
0.020 – 0.038
0.020 – 0.081
Measure HTE06 assumes an improved U Value for the External Wall, which varies upon location. Table 11 serves
as an example to achieve a U Value of 0.45W/m² K, providing the thickness of certain insulation materials. The
actual thickness required will depend on many other factors, including the fixing method, wall construction, and
the position of the insulation within the material layers.
Table 11: Thickness of insulation required to achieve a U Value of 0.45 W/m² K 13
Thickness (mm)
Insulation Type
Approximate values to achieve a U Value
of 0.45W/m2 K
Vacuum Insulated Panels
10 - 20mm
Polyurethane (PU)
40 - 80mm
Polyisocyanurate (PIR)
40 - 60mm
Phenolic Foam (PF)
40 - 55mm
Expanded Polystyrene
60 - 95mm
Extruded Polystyrene
Wool and Fiber
50 - 80mm
60 - 130mm
Relationship to Other Measures
Selecting this measure will show an increase in the environmental impact in the materials section due to the
addition of insulation material (reflected as a negative percentage improvement).
12
Source: Insulation Materials Chart, Energy Savings Trust, 2004
13
Source: Insulation Materials Chart, Energy Savings Trust, 2004
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ENERGY EFFICIENCY MEASURES
By increasing the level of insulation, the heating and/or cooling loads will be reduced. Increasing the levels of
insulation could therefore reduce the cost and environmental impact of the heating and cooling plant.
Assumptions
The insulation fitted within the external walls for the base case varies by location, which is revealed in the U
Value shown in the Key Assumptions for the Base Case in the Design section. The improved case assumes that
the actual U Value will be better (lower) than the base case as listed in the Key Assumptions for the Base Case.
Compliance Guidance
In order to claim this measure, it will be necessary to demonstrate that the U Value of the complete external
walls specification is better (lower) than the base case as listed in the Key Assumptions for the Base Case in the
Design section. If the improved case U Value is used then it is only necessary to demonstrate that insulation has
been or will be installed, and that the U Value of the External Walls does not exceed the base case.
If a U Value is being entered that exceeds the improved case then it is necessary to confirm that the U Value
has been calculated in accordance with the “simple” or “combined” method as shown in
Approach/Methodologies above.
If U Value of wall is worse (higher) than base case, it is necessary to enter the higher U value and
select the insulation of the wall under energy tab HTE04.
Design Stage
At the design stage the following must be used to
demonstrate compliance:



External walls construction detail drawing showing
the insulation material. Ideally the external walls
detail drawing should be annotated with the U
Value of the external walls.
Calculations of U value either using the formula or
U value calculators.
Manufacturer’s data sheet of specified insulation
material for the external walls.
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Post-Construction Stage
Since at the post-construction stage the insulation
material will not be visible, it must be demonstrated
that the insulation material specified at the design
stage was delivered to the site. One or all of the
following must be used to demonstrate compliance:


Delivery note confirming that the insulation
material was delivered to the site.
Photographs of the external walls construction at a
point when the insulation material was visible.
Updated calculations for U value if the thickness
and type of insulations changed from the original
design.
29
ENERGY EFFICIENCY MEASURES
HTE05 – LOW-E COATED GLASS
Requirement Summary
This measure can be claimed if Low Emissivity (Low-E) coated glazing is used.
Intention
The purpose of adding a Low-E coating to glazing is that it reduces the transference of heat from one side to the
other by reflecting thermal energy. Low-E coatings are microscopically thin metal or metallic oxide layers that
are deposited on a glass surface to help keep heat on the same side of the glass from which it originated. In
warm climates the intention is to reduce heat gain and in cold climates the intention is to reflect heat indoors.
Approach/Methodologies
Low-E coating reduces the Solar Heat Gain Coefficient (SHGC) and thermal resistance (U Value) of the glazing.
This measure assumes a U Value of 3W/m²K and an SHGC of 0.45 for glazing. These concepts are explained as
follows:
The SHGC is expressed as a number between 0 and 1 and indicates the proportion of infrared radiation (heat)
that is permitted to pass through the glazing.
All Low-E glass will have a reduced U Value, however it is the product’s solar heat gain performance that
determines whether it is appropriate for a certain climate. For warm climates, Low-E glass with a low SHGC
helps reduce unwanted solar gains but in cold climates, Low-E glazing that has minimal impact on solar gains is
required.
In both warm and cold climates, the lower U Value of Low-E glazing is an advantage. Manufacturers often
provide separate U Values for summer and winter (or the heating and cooling seasons). A simple approach is to
calculate the average of these two values. If an alternative approach is used to calculate the seasonal average
then this must be clearly justified. One example of an acceptable justification is if there is no heating season
where the building is located.
Potential Technologies/Strategies
Low-E coating is applied to different sides of the glazing depending on the climate. In a warm climate the
coating is usually applied on the inner surface as this helps to reflect the solar radiation back outside. In a cold
climate the coating is usually applied on the outer surface to allow useful solar radiation to pass through to
passively heat the interior, and to reduce the ability for infrared radiation to pass out.
There are two types of Low-E coating: hard coat and soft coat. Only hard coat (pyrolitic coating) should be used
in single-glazed units as it is more durable than soft coat (sputter coating).

Hard Coat Low-E: Hard coat Low-E, or pyrolytic coating, is a coating applied at high temperatures
and is sprayed onto the glass surface during the float glass process. The coating process, known as
Chemical Vapor Deposition (CVD), uses a variety of different chemicals including silicon, silicon oxides,
titanium dioxide, aluminum, tungsten, and many others. The vapor is directed at the glass surface and
forms a covalent bond with the glass, so the result is hard wearing.

Soft Coat Low-E: Soft coat Low-E, or sputter coating, is applied in multiple layers of optically
transparent silver sandwiched between layers of metal oxide in a vacuum chamber. This process
provides the highest level of performance and a nearly invisible coating, however it is highly
susceptible to damage from handling (recommended in double glazing units).
As guidance, Table 12 shows a range of U Values and SHGC values for different types of glazing. However, this
data varies from manufacturer to manufacturer, for certification purposes actual values from the manufacturer
must be provided.
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ENERGY EFFICIENCY MEASURES
Table 12: Approximate SHGC and U Values for different glazing types
Glass Configuration
Approximate
SHGC
Approximate U
Value [W/m2
K]
Type of
Glass
Performance
Thickness
(mm)
Color
Single
glass
Hard (Pyrolitic)
Double
glass
Soft (sputtered)
6 mm
8 mm
6 mm
6 mm
8 mm
6 mm
8 mm
6 mm
8 mm
6 mm
(12mm gap)
6 mm
(12mm gap)
6 mm
(12mm gap)
6 mm
(12mm gap)
6 mm
(12mm gap)
Blue / Green
Blue / Green
Bronze
Grey
Grey
Clear
Clear
Gold
Gold
Blue / Green
0.31 -0.49
0.30 -0.37
0.42 - 0.45
0.36 -0.41
0.32
0.48-0.62
0.51
0.54 - 0.55
0.52
0.15 - 0.41
3.7 -5.7
3.6 - 3.8
3.8 -5.7
3.7 - 5.7
3.6
3.7 - 5.7
3.7
5.7
5.7
1.5 - 2.8
Clear
0.29 -0.59
1.5 -1.6
Bronze
0.22 -0.30
1.5 - 1.6
Grey
0.13 -0.28
1.5 - 1.6
Gold
0.32
1.6
Relationship to Other Measures
Applying a Low-E coating either reduces the heat load by reducing the heat loss through the glazing, or reduces
the cooling load by reducing the solar heat gain. As with other measures which relate to the improvement of the
building fabric, it is often cheaper to address and optimize performance before sizing/selecting heating,
ventilation, and the air-conditioning plant. If Higher Performance Glass (HTE08) is claimed then this measure
will not contribute to the calculation of savings.
Special care must be taken in cold climates, because as the U Value is reduced, the solar heat gain is reduced
even further for many coatings. Therefore, although a Low-E glass with a very low U Value appears to be the
best choice, it may actually have worse performance if it has low solar heat gain that blocks the warmth of the
sun and increases heating requirements. In those cases a double or triple layer glass with a high solar heat gain
coefficient is the right selection.
Assumptions
The base cases for the U Value and SHGC of glass are included in the Key Assumptions for the Base Case in the
Design section. The improved case assumptions for Low-E coated glass are a U Value of 3 W/m² K and an SHGC
of 0.45.
If U Value of selected glass is worse (higher) than base case, it is necessary to enter the higher U value and
select the “Low-E Coated Glass - U Value of 3 W/m² K and SHGC of 0.45” under energy tab HTE05. This would
happen in countries where double glazing is norm for hotel buildings. The same principle is applicable for SHGC,
i.e. if the SHGC is different from the base case assumption the actual SHGC should be entered to the HTE05 and
it should be selected.
Compliance Guidance
The following information must be provided to show compliance at the design and post-construction stages:
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Manufacturer’s data sheets showing the seasonal
average U Value for the glazing (including losses
through the glass and frame) and the solar heat
gain coefficient (SHGC) of the glass.
A list of different types of window included in the
design (window schedule).
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Photographs of the glazing units installed.
Purchase receipts and delivery notes for the
glazing.
Manufacturer’s data sheets showing the seasonal
average U Value for the glazing (including losses
through the glass and frame) and the solar heat
gain coefficient (SHGC) of the glass.
31
ENERGY EFFICIENCY MEASURES
HTE06 – HIGHER THERMAL PERFORMANCE GLASS
Requirement Summary
This measure can be claimed if the glazing is multi-paned (double or triple) and has a superior thermal
performance.
Intention
By selecting double or triple glazing, which has an improved thermal performance as well as a coating (tinted
glass or Low-E) the heat transfer is reduced further than in HTE05 and an even lower SHGC can be achieved.
Approach/Methodologies
Low-E coating reduces the solar heat gain coefficient (SHGC) and thermal resistance (U Value) of the glazing.
The SHGC is expressed as a number between 0 and 1 and indicates the proportion of infrared radiation (heat)
that is permitted to pass through the glazing.
All Low-E glass will have a reduced U Value however it is the product’s solar heat gain performance that
determines whether it is appropriate for a certain climate. For warm climates, Low-E glass with a low SHGC
helps reduce unwanted solar gains but in cold climates, Low-E glazing that has minimal impact on solar gains is
required.
In both warm and cold climates, the lower U Value of Low-E glazing is an advantage. Manufacturers often
provide separate U Values for summer and winter (or the heating and cooling seasons). A simple approach is to
calculate the average of these two values. If an alternative approach is used to calculate the seasonal average,
then this must be clearly justified. One example of an acceptable justification is if there is no heating season
where the building is located.
Potential Technologies/Strategies
Low-E coating is applied to different sides of the glazing depending on the climate. In a warm climate the
coating is usually applied on the inner surface as this helps to reflect the solar radiation back outside. In a cold
climate the coating is usually applied on the outer surface to allow useful solar radiation to pass through to
passively heat the interior, and to reduce the ability for infrared radiation to pass out.
There are two types of Low-E coating: hard coat and soft coat. Only hard coat (pyrolitic coating) should be used
in single-glazed units as it is more durable than soft coat (sputter coating).

Hard Coat Low-E: Hard coat Low-E, or pyrolytic coating, is a coating applied at high temperatures
and is sprayed onto the glass surface during the float glass process. The coating process, known as
Chemical Vapor Deposition (CVD), uses a variety of different chemicals including silicon, silicon oxides,
titanium dioxide, aluminum, tungsten, and many others. The vapor is directed at the glass surface and
forms a covalent bond with the glass, so the result is hard wearing.

Soft Coat Low-E: Soft coat Low-E, or sputter coating, is applied in multiple layers of optically
transparent silver sandwiched between layers of metal oxide in a vacuum chamber. This process
provides the highest level of performance and a nearly invisible coating, but it should only be used in
double-glazing as it is highly susceptible to damage from handling.
In the absence of the manufacturer’s actual data Table 13 can be used as a guide. It contains typical U Values
and SHGC values for different types of glazing. For certification purposes actual values must be provided.
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ENERGY EFFICIENCY MEASURES
Table 13: Approximate SHGC and U Values for different glazing types.
Frame Material
Timber or PVC-U
Metal
Approximate
SHGC
Approximate U Value in W/m2
K (assuming 12mm air gap for
double and triple glazing; lower
U Values can be achieved with a
larger air gap)
Double
0.53-0.76
2.7-2.8
Double (Hard Coat)
0.50-0.72
2.0-2.2
Double (Soft Coat)
0.44-0.63
1.8-2.1
Triple
0.48-0.68
2.0-2.1
Triple (Hard Coat)
0.45-0.64
1.5-1.7
Triple (Soft Coat)
0.40-0.57
1.4-1.6
Single
0.68-0.85
5.7
Double
0.61-0.76
3.3-3.4
Double (Hard Coat)
0.58-0.72
2.5-2.8
Double (Soft Coat)
0.50-0.63
2.4-2.6
Triple
0.54-0.68
2.5-2.6
Triple (Hard Coat)
0.51-0.64
1.9-2.1
Triple (Soft Coat)
0.46-0.57
1.8-2.0
Type of Glazing
Source: The Government’s [UK] Standard Assessment Procedure for Energy Rating of Dwellings SAP 2009 (March 2010)
Relationship to Other Measures
Applying a Low-E coating either decreases the heat load by reducing the heat loss through the glazing, or
decreases the cooling load by reducing the solar heat gain. As with other measures which relate to the
improvement of the building fabric, it is often cheaper to address and optimize performance before
sizing/selecting heating, ventilation, and the air-conditioning plant.
If the measure for Low-E Coated Glass (HTE05) is claimed in addition to HTE06, then only the results of HTE06
will contribute to the calculation of savings.
Special care must be taken in cold climates, because as the U Value is reduced, the solar heat gain is reduced
even further for many coatings. Therefore, although a Low-E glass with a very low U Value appears to be the
best choice, it may actually have worse performance if it has low solar heat gain that blocks the warmth of the
sun and increases heating requirements.
Assumptions
The base cases for the U Value and SHGC for glass are included in the Key Assumptions for the Base Case in the
Design section. The improved case assumptions for higher thermal performance glass are a U Value of 1.95
W/m² K and an SHGC of 0.28.
Compliance Guidance
The following information must be provided to show the compliance at the design and post-construction stages:
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Manufacturer’s data sheets showing the seasonal
average U Value for the glazing (including losses
through the glass and frame) and the solar heat
gain coefficient (SHGC) of the glass.
A list of different types of window included in the
design (window schedule).
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Photographs of the glazing units installed.
Purchase receipts and delivery notes for the
glazing.
Manufacturer’s data sheets showing the seasonal
average U Value for the glazing (including losses
through the glass and frame) and the solar heat
gain coefficient (SHGC) of the glass.
33
ENERGY EFFICIENCY MEASURES
HTE07 – NATURAL VENTILATION – CORRIDORS
Requirement Summary
This measure can be claimed when two conditions are met. The first one is the corridor 'room depth to ceiling
height ratio' and the proportion of openings required for a certain floor area. Both conditions should be
calculated in each corridor in order to ensure adequate natural ventilation for the whole communal area of the
hotel. The methodology for this calculation is explained below.
Intention
A well-designed natural ventilation strategy can improve occupant comfort by providing both access to fresh air
as well as reducing the temperature. This results in a reduction of the cooling load, which lowers initial capital
and maintenance costs.
Approach/Methodologies
There are no complex units of measurement used to assess compliance with this measure. Instead some simple
conditions (“rules of thumb”) can be used to help design spaces for the benefit of human comfort. The key
factors in deciding the ventilation strategy are room size (depth, width, and height), and the number and
location of openings.
Potential Technologies/Strategies
EDGE uses cross flow ventilation, where fresh air is drawn from outside into the occupied space and the exhaust
air is delivered at a different location, as explained in Table 14. This type of ventilation is used for the improved
case as it is most effective if the external air temperature is neither too hot nor too cold (temperate climates).
As EDGE takes into account the external temperature it is possible to test the potential effectiveness by using
the software. If EDGE predicts significant savings then a suitable strategy should be considered.
There are two basic approaches to the design of cross ventilation: single-sided and two-sided. Two-sided
ventilation is used to ventilate single spaces (which have openings on both windward and leeward sides) and
double-banked rooms that rely on openings in corridors between rooms. Single-sided ventilation is used where
two-sided ventilation is not possible, but the room depth that can be ventilated in this way is much lower.
Table 14: Type of cross ventilation
Type
Image
Single-sided
Ventilation
Cross-ventilation
- Single Spaces
Cross-ventilation
- Double-Banked
Spaces
Description
Single-sided ventilation relies on the pressure differences between
different openings within a single space. It is more predictable and
effective than if there is only a single opening, and can therefore be used
for spaces with greater depth. For spaces that only have a single opening
the ventilation is driven by turbulence. This turbulence creates a pumping
action on the single opening, causing small inflows and outflows. As this is
a less predictable method, the room depth for single opening, single-sided
ventilation is reduced.
Cross ventilation of single spaces is the simplest and most effective
approach. Cross-ventilation is driven by pressure differences between the
windward and leeward sides of the space.
Cross-ventilation with banked rooms can be achieved by creating openings
in the corridor partition. It is only acceptable where a room has ownership
of both windward and leeward sides of the building, as the ventilation of
the leeward space relies on the occupant of the windward space. The
openings also provide a route for noise to travel between spaces.
One potential solution is to provide a channel which bypasses the
windward space, allowing the occupant of the leeward space complete
control of air flow.
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ENERGY EFFICIENCY MEASURES
Stack Ventilation
Stack ventilation takes advantage of the temperature stratification and
associated pressure differentials of the air. Warm air becomes less dense
and rises and the cooler air replaces the air that has risen. This type of
ventilation requires atriums or height differences.
In order to achieve acceptable natural ventilation flow, the following methodology must be considered: i)
maximum ratio of floor depth to ceiling height, and ii) the heat gains to be dissipated, which determine the total
area of the opening. The latter is simplified by only providing the % of floor area as openable area.
Room Depth to Ceiling Height Ratio
EDGE’s methodology for natural ventilation first requires that the maximum room depth versus ceiling height is
calculated following the ratio in Table 15.
The depth of space that can be ventilated using a cross flow ventilation strategy is dependent on the floor to
ceiling height and the number and location of the openings. The rules of thumb below can be used to assess
compliance.
Table 15: Depth of floor to ceiling height ratio for different room configurations
Room/Opening
Configuration
Image/Example
Maximum Depth of
Floor to Ceiling
Height Ratio
Single-sided,
single opening
1.5
Single-sided,
multiple
openings
2.5
5.0
Cross ventilation
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ENERGY EFFICIENCY MEASURES
Minimum Area of Opening
As the heat gain in a hotel corridor is relatively small, the window area should be at least 10% of floor area of
corridor.
Table 16: Total area of opening as a proportion of floor area for different heat gain ranges.
Room type
Heat Gains
Total Area of Opening Required
as a Percentage of Floor Area
Corridor
<15 W/m²
10%
Example:
Q: A corridor with 20sqm floor area and ceiling height of 3m has 2 windows for ventilation. What is the design
criteria to ensure compliance with natural ventilation requirements?
A: Depth of floor to ceiling height ratio should be less than 5, i.e. the plan can be 2mx10m where 10m is the
depth.
10% of the floor area should be openable which is: 2m2 making each window 1m2.
Relationship to Other Measures
Since employing natural ventilation can significantly reduce the cooling load, the impact of more efficient cooling
systems is sometimes reduced to an insignificant level. As with all passive design solutions, cross ventilation
should therefore be considered before the detailed design of any HVAC equipment.
Assumptions
The base case assumes that ventilation is delivered using mechanical means; however the cooling load is still
calculated and is shown as “virtual” energy on the charts.
The cooling load can be reduced through other passive measures, including improved insulation, reduced
window to wall ratio, reduced SHGC, improved solar shading, and specifying ceiling fans. Reducing the cooling
load will therefore result in improved performance even when no mechanical cooling is specified.
Compliance Guidance
If this measure is claimed then the design team will need to demonstrate compliance with the depth of floor to
ceiling height ratio and minimum area of opening for all corridors.
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Typical floor plans for every floor showing
corridors’ layouts and the location of openings.
Typical sections showing the floor to ceiling height
for every floor.
Calculations showing the depth to ceiling height
ratio and minimum area of opening for each typical
space.
International Finance Corporation
Post-Construction Stage
At the post-construction stage one of the following
must be used to demonstrate compliance:



As-built drawings including floor plans and sections.
Confirmation from the project team that there have
been no changes to the layout or the floor to ceiling
height during the design/construction process.
Photographic evidence to demonstrate that the
corridor layouts and location of openings as
specified at the design stage have been
constructed.
36
ENERGY EFFICIENCY MEASURES
HTE08 – NATURAL VENTILATION – GUEST ROOMS WITH AUTO CONTROL
Requirement Summary
This measure can be claimed when two conditions are met. The first one is the room depth to ceiling height
ratio and the proportion of openings required for a certain floor area. Both conditions should be calculated in
each guest room in order to ensure adequate natural ventilation for the guest rooms of the hotel. The
methodology for this calculation is explained below.
Intention
A well-designed natural ventilation strategy can improve occupant comfort by providing both access to fresh air
as well as reducing the temperature. This results in a reduction of the cooling load, which lowers initial capital
and maintenance costs.
Approach/Methodologies
There are no complex units of measurement used to assess compliance with this measure. Instead some simple
conditions (“rules of thumb”) can be used to help design spaces for the benefit of human comfort. The key
factors in deciding the ventilation strategy are room size (depth, width, and height), and the number and
location of openings.
Potential Technologies/Strategies
EDGE uses cross flow ventilation, where fresh air is drawn from outside into the occupied space and the exhaust
air is delivered at a different location, as explained in Table 17. This type of ventilation is used for the improved
case as it is most effective if the external air temperature is neither too hot nor too cold (temperate climates).
As EDGE takes into account the external temperature it is possible to test the potential effectiveness by using
the software. If EDGE predicts significant savings then a suitable strategy should be considered.
There are two basic approaches to the design of cross ventilation: single-sided and two-sided. Two-sided
ventilation is used to ventilate single spaces (which have openings on both windward and leeward sides) and
double-banked rooms that rely on openings in corridors between rooms. Single-sided ventilation is used where
two-sided ventilation is not possible, but the room depth that can be ventilated in this way is much lower.
Table 17: Type of cross ventilation
Type
Image
Single-sided
Ventilation
Cross-ventilation
- Single Spaces
Cross-ventilation
- Double-Banked
Spaces
Description
Single-sided ventilation relies on the pressure differences between
different openings within a single space. It is more predictable and
effective than if there is only a single opening, and can therefore be used
for spaces with greater depth. For spaces that only have a single opening
the ventilation is driven by turbulence. This turbulence creates a pumping
action on the single opening, causing small inflows and outflows. As this is
a less predictable method, the room depth for single opening, single-sided
ventilation is reduced.
Cross ventilation of single spaces is the simplest and most effective
approach. Cross-ventilation is driven by pressure differences between the
windward and leeward sides of the space.
Cross-ventilation with banked rooms can be achieved by creating openings
in the corridor partition. It is only acceptable where a room has both
windward and leeward sides of the building, as the ventilation of the
leeward space relies on the occupant of the windward space. The openings
also provide a route for noise to travel between spaces.
One potential solution is to provide a channel which bypasses the
windward space, allowing the occupant of the leeward space complete
control of air flow.
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ENERGY EFFICIENCY MEASURES
Stack ventilation takes advantage of the temperature stratification and
associated pressure differentials of the air. Warm air becomes less dense
and rises and the cooler air replaces the air that has risen. This type of
ventilation requires atriums or height differences.
Stack Ventilation
In order to achieve acceptable natural ventilation flow, the following methodology must be considered: i)
maximum ratio of floor depth to ceiling height, and ii) the heat gains to be dissipated, which determine the total
area of the opening. The latter is simplified by providing the % of floor area as openable area.
Room Depth to Ceiling Height Ratio
EDGE’s methodology for natural ventilation first requires that the maximum room depth versus ceiling height is
calculated following the ratio in Table 18.
The depth of space that can be ventilated using a cross flow ventilation strategy is dependent on the floor to
ceiling height and the number and location of the openings. The rules of thumb below can be used to assess
compliance.
Table 18: Depth of floor to ceiling height ratio for different room configurations
Room/Opening
Configuration
Image/Example
Maximum Depth of
Floor to Ceiling
Height Ratio
Single-sided,
single opening
1.5
Single-sided,
multiple
openings
2.5
5.0
Cross ventilation
Minimum Area of Opening
When heat gains per room are calculated, Table 19 indicates the percentage of the opening area required in
order to dissipate those heat gains within the space. The area of opening can be calculated by multiplying the
total area of the room by the 20%.
Table 19: Total area of opening as a proportion of floor area for hotel guest rooms
Room type
Heat Gains
Total Area of Opening Required
as a Percentage of Floor Area
Guest room
15-30 W/m²
20%
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ENERGY EFFICIENCY MEASURES
Example:
Q: A living room with 16sqm floor area and ceiling height of 3m has a single window for ventilation. What is the
design criteria to ensure compliance with natural ventilation requirements?
A: Depth of floor to ceiling height ratio should be less than 1.5, i.e. the plan can be 4mx4m where 4m is the
depth.
As 20% of floor area should be openable which is: 3.2m2. This can be provided by a French door of 2m high
and 1.6m width.
Relationship to Other Measures
Since employing natural ventilation can significantly reduce the cooling load, the impact of more efficient cooling
systems is sometimes reduced to an insignificant level. As with all passive design solutions, cross ventilation
should therefore be considered before the detailed design of any HVAC equipment.
Assumptions
The base case assumes that ventilation is delivered using mechanical means; however the cooling load is still
calculated and is shown as “virtual” energy on the charts.
The cooling load can be reduced through other passive measures, including improved insulation, reduced
window to wall ratio, reduced SHGC, improved solar shading, and specifying ceiling fans. Reducing the cooling
load will therefore result in improved performance even when no mechanical cooling is specified.
Compliance Guidance
If this measure is claimed then the design team will need to demonstrate compliance with the depth of floor to
ceiling height ratio and minimum area of opening for all guest rooms.
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Typical floor plans for every floor showing room
layouts and the location of openings.
Typical sections showing the floor to ceiling height
for every floor.
Calculations showing the room depth to ceiling
height ratio and minimum area of opening for each
typical space.
International Finance Corporation
Post-Construction Stage
At the post-construction stage one of the following
must be used to demonstrate compliance:



As-built drawings including floor plans and sections.
Confirmation from the project team that there have
been no changes to the layout or the floor to ceiling
height during the design/construction process.
Photographic evidence to demonstrate that the
room layouts and location of openings as specified
at the design stage have been constructed.
39
ENERGY EFFICIENCY MEASURES
HTE09 – VARIABLE REFRIGERANT VOLUME (VRV) COOLING SYSTEM
Requirement Summary
This measure can be claimed if the air conditioning system achieves a Coefficient of Performance (COP) greater
than 3.5 under ARI condition.
Intention
In many cases, cooling will not be a part of the original build, which may increase the risk that future occupants
will deal with any overheating with an amateur installation of inefficient and poorly sized air conditioning units.
By designing the installation of an efficient cooling system, the energy needed to deliver the required cooling
will be reduced.
Approach/Methodologies
EDGE uses the Coefficient of Performance (COP) to measure the efficiency of air conditioning systems. The COP
is the total output of cooling energy per electricity input. The COP for cooling is defined as the ratio of the rate
of heating energy removal to the rate of electrical energy input, in consistent units, for a complete air
conditioning system or some specific portion of that system under designated operating conditions. For
consistency the ARI conditions should be used for comparison of COP values.
In order to claim this measure the design team must demonstrate that the chiller(s) achieve a COP greater than
the base case of 3.5. For large buildings with centralized systems, more than one chiller may be installed. If
these chillers have different COPs, the weighted average COP should be calculated.
Potential Technologies/Strategies
A Variable Refrigerant Volume/Variable Refrigerant Flow (VRV/VRF) chiller uses the refrigerant as the
cooling/heating medium. These systems have one condensing unit with multiple indoor units, each of which can
be individually controlled. The system runs by modulating the amount of refrigerant that is sent to each
evaporator. By operating at differing speeds, the system runs only at the rate needed to deliver the cooling
required by each internal unit.
VRV or VRF systems may be the best for buildings with multiple zones or wide variance heating/cooling loads
across many different internal zones requiring individual control such as office buildings, hospitals, or hotels.
The outdoor units can be fitted to as many as 48 internal units. Due to the way the internal units are connected
to the external unit, a breakdown of one internal unit will not compromise the rest of the system. The outdoor
units are capable of changing the speed of the compressors and can therefore operate in a range of 6% to
100% capacity. Multiple outdoor units can be used if an even greater range of capacity is required.
Some typical efficiency recommended by ASHRAE 90.1-2010 are listed in Table 20 highlighting the VRV system:
Table 20: Typical COPs for different types of air conditioning systems14.
Type of Air Conditioning System
Split < 65.000 BTU/h
Variable Refrigerant Volume
Split Duct
Air Cooled Chiller < 150 TR ( reciprocating)
Air Cooled Chiller < 150 TR (screw)
Air Cooled Chiller > 150 TR ( reciprocating)
Air Cooled Chiller > 150 TR (screw)
Water Cooled Chiller < 150 TR ( reciprocating)
Water Cooled Chiller < 150 TR (screw)
Water Cooled Chiller > 150 TR ( reciprocating)
Water Cooled Chiller > 150 TR (screw)
Water Cooled Chiller > 300 TR (centrifugal)
14
COP
2.70
3.70
2.60
2.80
2.90
2.80
3.00
4.00
4.10
4.26
4.40
6.05
Source: ASHRAE 90.1-2010
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
EDGE calculates the cooling load by taking account of the local climate, heat gains, and the internal
temperatures based on the building design. If air conditioning is not specified, any cooling load will be displayed
as “virtual energy.”
Assumptions
The base case for air conditioning system efficiency is a COP of 2.66, and is listed in the Key Assumptions for
the Base Case in the Design section. The base case can be over-written with the minimum COP required by local
codes where they are in existence. If the key assumption is overwritten, then justification and documentation
for local regulations must be provided. The improved case COP for the VRV/VRF cooling system is 3.5; if the
system efficiency is higher than 3.5 then the actual performance can be entered and the energy savings will be
even greater.
Compliance Guidance
In order to demonstrate compliance, the design team must describe the specified system and provide
documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Manufacturer’s data sheets for the VRV cooling
system specifying COP information.
For systems including more than one chiller unit,
the design team must provide the average COP
calculation.
Mechanical drawings showing the location of the
external and internal units.
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




As-built mechanical drawings with air conditioning
schematics.
Delivery notes showing that specified chillers have
been delivered to the site.
Manufacturer’s data sheets for the VRV cooling
system specifying COP information.
Photographs of installed external and internal air
conditioning units.
41
ENERGY EFFICIENCY MEASURES
HTE10 – AIR CONDITIONING WITH AIR COOLED SCREW CHILLER
Requirement Summary
This measure can be claimed if the air conditioning system achieves a Coefficient of Performance (COP) greater
than 3.2 under ARI condition.
Intention
In many cases, cooling will not be a part of the original build, which may increase the risk that future occupants
will deal with any overheating with an amateur installation of inefficient and poorly sized air conditioning units.
By designing the installation of a mechanical refrigeration system using chilled air as a distributing unit, the
energy needed to deliver the required cooling will be reduced. Air cooled chillers are suitable for climates where
water supply is scarce or high humidity reduces the efficiency of cooling towers.
Approach/Methodologies
EDGE uses the Coefficient of Performance (COP) to measure the efficiency of air conditioning systems. The COP
is the total output of cooling energy per electricity input. The COP for cooling is defined as the ratio of the rate
of heating energy removal to the rate of electrical energy input, in consistent units, for a complete air
conditioning system or some specific portion of that system under designated operating conditions. For
consistency the ARI conditions should be used for comparison of COP values.
In order to claim this measure the design team must demonstrate that the chiller(s) achieve a COP greater than
the base case of 3.2. For large buildings with centralized systems, more than one chiller may be installed. If
these chillers have different COPs, the weighted average COP should be calculated.
Potential Technologies/Strategies
This technology is based on a chiller, which is a vapor compression mechanical refrigeration system. It has four
components: i) Compressor, ii) Condenser, iii) Thermal expansion valve, and iv) Evaporator, the last one is a
heat exchanger in which heat captured by the process is transferred to the refrigerant fluid. This heat-transfer
makes the refrigerant evaporates, changing from liquid (a low pressure) to vapor, therefore the temperature of
the process coolant is decreased to the desired leaving temperature. In this technology the chiller has a screw
compressor, which uses a rotary type positive displacement mechanism with two meshing screw-rotors that
rotate in opposite directions, trapping the refrigerant vapor and reducing the volume of the refrigerant to the
discharge point (condenser).
Air cooled chillers cost significantly less per ton than water-cooled systems primarily because they require fewer
components to build and operate, and require less support equipment and plumbing. Installation of air cooled
chiller is faster and easier than that of water cooled chiller.
Some typical efficiency recommended by ASHRAE 90.1-2010 are listed in Table 21 highlighting the Air Cooled
Screw Chiller system:
Table 21: Typical COPs for different types of air conditioning systems 15
Type of Air Conditioning System
Split < 65.000 BTU/h
Variable Refrigerant Volume
Split Duct
Air Cooled Chiller < 150 TR ( reciprocating)
Air Cooled Chiller < 150 TR (screw)
Air Cooled Chiller > 150 TR ( reciprocating)
Air Cooled Chiller > 150 TR (screw)
Water Cooled Chiller < 150 TR ( reciprocating)
Water Cooled Chiller < 150 TR (screw)
Water Cooled Chiller > 150 TR ( reciprocating)
Water Cooled Chiller > 150 TR (screw)
Water Cooled Chiller > 300 TR (centrifugal)
15
COP
2.70
3.70
2.60
2.80
2.90
2.80
3.00
4.00
4.10
4.26
4.40
6.05
Source: ASHRAE 90.1-2010
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
EDGE calculates the cooling load by taking account of the local climate, heat gains, and the internal
temperatures based on the building design. If air conditioning is not specified, any cooling load will be displayed
as “virtual energy.”
Assumptions
The base case for air conditioning system efficiency is a COP of 2.66, and is listed in the Key Assumptions for
the Base Case in the Design section. The base case can be over-written with the minimum COP required by local
codes where they are in existence. If the key assumption is overwritten, then justification and documentation
for local regulations must be provided. The improved case COP for the Air Cooled Screw Chiller system is 3.2; if
the system efficiency is higher than 3.2 then the actual performance can be entered and the energy savings will
be even greater.
Compliance Guidance
In order to demonstrate compliance, the design team must describe the specified system and provide
documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Manufacturer’s data sheets for the Air cooled screw
chiller system specifying COP information.
For systems including more than one chiller unit,
the design team must provide the average COP
calculation.
Mechanical layout drawings showing the location of
the external and internal units
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




As-built mechanical drawings with air conditioning
schematics
Delivery notes showing that specified chillers have
been delivered to the site.
Manufacturer’s data sheets for the Air Cooled screw
chiller system specifying COP information.
Photographs of installed external and internal air
conditioning units.
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ENERGY EFFICIENCY MEASURES
HTE11 – AIR CONDITIONING WITH WATER COOLED CHILLER
Requirement Summary
This measure can be claimed if the air conditioning system achieves a Coefficient of Performance (COP) greater
than the base case, as set out in the Key Assumptions for the Base Case in the Design section. The COP will be
checked under ARI condition.
Intention
If reducing operating costs is a paramount concern and the project can invest in systems and facilities for a long
period, a water cooled system might be the best option. Water cooling involves a higher initial investment since
these systems require both a chiller and a circulating tower system, which in turn will require additional pumps,
piping, and tanks. Furthermore, water cooling systems will consume considerable amounts of water due to
evaporation, purging, and bleeding.
Approach/Methodologies
EDGE uses the Coefficient of Performance (COP) to measure the efficiency of air conditioning systems. The COP
is the total output of cooling energy per electricity input. The COP for cooling is defined as the ratio of the rate
of heating energy removal to the rate of electrical energy input, in consistent units, for a complete air
conditioning system or some specific portion of that system under designated operating conditions. For
consistency the ARI conditions should be used for comparison of COP values.
In order to claim this measure the design team must demonstrate that the chiller(s) achieve a COP greater than
the base case. For large buildings with centralized systems, more than one chiller may be installed. If these
chillers have different COPs, the weighted average COP should be calculated.
Potential Technologies/Strategies
This technology is similar to air cooled chillers, the primary difference is that water is used to provide the
condenser cooling.
The cycle begins in the evaporator where a liquid refrigerant flows over the evaporator tube bundle and
evaporates, absorbing heat from the chilled water circulating through the bundle. The refrigerant vapor is drawn
out of the evaporator by the compressor. The compressor then “pumps” the refrigerant vapor to the condenser
raising its pressure and temperature. The refrigerant condenses on or in the condenser tubes, giving up its heat
to the cooling water. The high pressure liquid refrigerant from the condenser then passes through the expansion
device that reduces the refrigerant pressure and temperature as it enters the evaporator. The refrigerant again
flows over the chilled water coils absorbing more heat and completing the cycle.
Relationship to Other Measures
EDGE calculates the cooling load by taking account of the local climate, heat gains, and the internal
temperatures based on the building design. If air conditioning is not specified, any cooling load will be displayed
as “virtual energy.”
In addition, when water cooled chiller is selected as an energy efficiency measure the water consumption is
increased for both base and improved case, as the chiller will require water to operate. Although, the general
water consumption is increased, the water savings are not impacted by this measure.
Assumptions
The base case for air conditioning system efficiency is a COP of 2.66, and is listed in the Key Assumptions for
the Base Case in the Design section. The base case can be over-written with the minimum COP required by local
codes where they are in existence. If the key assumption is overwritten, then justification and documentation
for local regulations must be provided. The improved case COP for the Water Cooled Chiller system vary
between 5.39 and 6.71; if the system efficiency is higher than specified as default by the measure, then the
actual performance can be entered and the energy savings will be even greater.
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ENERGY EFFICIENCY MEASURES
Compliance Guidance
In order to demonstrate compliance, the design team must describe the specified system and provide
documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:




Mechanical drawings with air conditioning
schematics for all floors.
Manufacturer’s data sheets for the Water cooled
chiller system specifying COP information.
For systems including more than one chiller unit,
the design team must provide the average COP
calculation.
Mechanical layout drawings/schematic showing the
location of the external and internal units.
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




As-built mechanical drawings with air conditioning
schematics for all floors if there are changes.
Delivery notes showing that specified chillers have
been delivered to the site.
Manufacturer’s data sheets for the Water cooled
chiller system specifying COP information.
Photographs of installed external and internal units
including chillers and cooling towers.
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ENERGY EFFICIENCY MEASURES
HTE12 – (GEOTHERMAL) GROUND SOURCE HEAT PUMP
Requirement Summary
This measure can be claimed if the Ground Source Heat Pump system achieves a Coefficient of Performance
(COP) greater than the base case, as set out in the Key Assumptions for the Base Case in the Design section.
The coefficient of performance (COP) is used in this measure to establish the efficiency. By default the base
case COP is 2.66 under ARI condition.
Intention
Ground source heat pumps (GHPs), sometimes referred to as geothermal heat pumps, are used to heat and
cool buildings by absorbing naturally existing heat from the earth. GHP’s use the constant below ground
temperature within the earth (soil or water) instead of using outside air temperature. Ground temperature is
warmer than air temperature during the winter and cooler than the air in the summer. The GHP takes
advantage of this by exchanging heat with the earth through a ground heat exchanger. GHP can reach high
efficiencies (300% to 600%) on the coldest winter nights, compared to air-source pumps that only reach up to
175% to 250% on cool days. Ground source heat pumps are a clean alternative in producing renewable and
reliable sources of energy16.
Approach/Methodologies
EDGE uses the Coefficient of Performance (COP) to measure the efficiency of Ground Source Heat Pumps. As
define in ASHRAE, the COP is the ‘ratio of the rate of heat delivered to the rate of energy input, in consistent
units, for a complete heat pump system, including the compressor and, if applicable, auxiliary heat, under
designated operating conditions’. For consistency the ARI conditions should be used for comparison of COP
values.
In order to claim this measure the design team must demonstrate that the Ground Source Heat Pump(s)
achieve a COP greater than the base case of 2.66. Efficient Ground Source Heat Pumps have COP that ranges
between 3.6 and 5.2.
Potential Technologies/Strategies
There are four major types of Ground Heat Pump Systems (GHP). Of the four major types, the horizontal,
vertical, and pond are closed loop systems. The fourth major type of GHP is the open loop system.
A closed loop system uses a loop of piping that is either buried in the ground or submerged under water. The
piping is filled with antifreeze or water that continuously circulates throughout the system. A heat exchanger
transfers heat between the refrigerant in the heat pump and the antifreeze/water solution in the closed loop
system. An open loop GHP system circulates water that is pumped from a ground or water source. Once the
heat is transferred into or out of the water, the water is discharged out of the system instead of being
recirculated again.
Table 22: Types of Ground Source Heat Pumps17.
System
Geothermal Heat Pump Type
Closed Loop
System
Horizontal
18
Process
A horizontal closed loop is usually the most cost
effective to buildings with adequate land space
available, in which trenches are easy to dig. This
type of installation is composed of pipes that run
horizontally in the ground. A slinky method is
sometimes used to loop or coil the pipes along the
bottom of a wide trench if there is not enough
adequate space for a true straight horizontal
system. Essentially, coiled loops are more
economically and space efficient.
16 Source: http://energy.gov/energysaver/articles/geothermal-heat-pumps and www.informedbuilding.com
17
Source: ASHRAE 90.1-2010
18 Source of all images in this table: courtesy of U.S Department of Energy
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ENERGY EFFICIENCY MEASURES
Closed Loop
System
Vertical
A vertical closed loop installation is usually most
cost-effective for building sites with limited
amount of land space or where existing landscape
is to be preserved. This type of installation is
composed of pipes that run vertically beneath the
ground. Holes are drilled in the ground, in which
each hole contains a single loop of pipe that
ranges from 30 to 100 meters deep. Vertical pipes
are then inserted and connected to a heat pump
within the building. This type is more expensive to
install due to the drilling, but less material (piping)
and land are required.
Closed Loop
System
Pond/Lake
A pond or lake closed loop system is used only if
there is at least an 2.5 meters deep body of water
in close proximity to a building property. A supply
line pipe runs underground from the building and
connects to large coiled pipes that are located
deep beneath the water. Due to advantages of
water-to-water heat transfer, a pond system is
both a highly economical and efficient option for a
heat pump.
Open Loop
System
Open Geothermal Loop System
An open geothermal loop system uses a well or
pond to pump fresh water into and back out of the
geothermal system. The water is used as the heat
exchange fluid that circulates within the GHP. An
abundant source of fresh clean water and a water
runoff area is essential for a successful open loop
system.
Relationship to Other Measures
EDGE calculates the cooling and heating load by taking account of the local climate, heat gains or losses, and
the internal temperatures based on the building design. If heating and/or cooling system(s) are not specified,
any cooling/heating load will be displayed as “virtual energy.”
In addition, when ground source heat pump is selected as an energy efficiency measure the heating and/ or
cooling energy is reduced depending on the load that the building has. The energy use by pumps is slightly
increased due to the operation of the system.
Assumptions
The base case for air conditioning system efficiency is a COP of 2.66, and for heating system is assumed to be
electric with a COP of 2.66, as listed in the Key Assumptions for the Base Case in the Design section. The base
case can be over-written with the minimum COP required by local codes where they are in existence. With
regards of the heating system the fuel can be over-written changing the efficiency for the base case. If the key
assumptions are overwritten, then justification and documentation for local regulations must be provided. The
improved case COP for the Ground Source Heat Pump system vary upon location between 3.6 and 5.2; if the
system efficiency is higher than specified as default by the measure, then the actual performance can be
entered and the energy savings will be even greater.
Compliance Guidance
In order to demonstrate compliance, the design team must describe the specified system and provide
documentation to support the claims.
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ENERGY EFFICIENCY MEASURES
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Manufacturer’s data sheets for the Ground Source
Heat Pump system specifying COP information.
Mechanical and electrical layout drawings showing
the location of the external loops and internal
equipment and distribution for all floors.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




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As-built mechanical and electrical drawings with
system schematics and distribution for all floors.
Delivery notes showing that specified system have
been delivered to the site.
Manufacturer’s data sheets for the Ground Source
Heat Pump system specifying COP information.
Photographs of the installation process of the
external loops and internal equipment installed.
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ENERGY EFFICIENCY MEASURES
HTE13 – ABSORPTION CHILLER POWERED BY WASTE HEAT
Requirement Summary
This measure can be claimed if the power generator, providing 100% of building energy at the peak load, is
running constantly and a recovery technology is installed to capture the waste heat for cooling cycle and the
absorption Chiller system achieves a Coefficient of Performance (COP) greater than 0.7 under ARI condition.
The coefficient of performance (COP) is used in this measure to establish the efficiency.
Intention
In many cases, cooling will not be a part of the original build, which may increase the risk that future occupants
will deal with any overheating with an amateur installation of inefficient and poorly sized air conditioning units.
By designing the installation of a mechanical refrigeration system using the waste heat generated in other
processes such as electricity generation or industrial processes and to run an absorption chiller, the energy
needed to deliver the required cooling and/ or heating will be reduced significantly.
Approach/Methodologies
EDGE uses the Coefficient of Performance (COP) to measure the efficiency of air conditioning systems. The COP
of absorption chillers is the total output of cooling energy per waste heat input. As define in ASHRAE, the COP is
the ‘the ratio of the rate of heat removal to the rate of energy input, in consistent units, for a complete
refrigerating system or some specific portion of that system under designated operating conditions’. Compared
to mechanical chillers, absorption chillers have a low coefficient of performance (COP = chiller load/heat input),
but they are powered by waste heat. For consistency the ARI conditions should be used for comparison of COP
values.
In order to claim this measure the design team must demonstrate that the absorption chiller(s) achieve an
efficiency greater than 70% (COP >0.7). For large buildings with centralized systems, more than one chiller
may be installed. If these chillers have different COPs, the weighted average COP should be calculated.
Potential Technologies/Strategies
An Absorption Chiller is a type of air cooling device that absorbs waste heat instead of mechanical energy to
provide cooling. Absorption chillers have a low coefficient of performance (COP). Therefore, they can reduce
operating costs because they are powered by low-grade waste heat. Absorption chillers are a much more cost
effective alternative to traditional cooling systems due to the lower costs attributed to the waste heat as fuel
and the low maintenance.
Waste heat is the result (byproduct) of industrial processes, oil and gas processing and is not being put to
practical use. Waste heat is captured to generate electricity with no additional emissions. It has a no cost fuel
source which can improve the overall energy efficiency in a facility.
A valuable alternative approach to improving overall energy efficiency is to capture and reuse the lost or "waste
heat" that is intrinsic to all industrial manufacturing. Captured and reused waste heat is an emission free
substitute for costly purchased fuels or electricity. Absorption chillers are more cost effective in large size
hotels, which are own and operated by the same manager.
Relationship to Other Measures
EDGE calculates the cooling and heating load by taking account of the local climate, heat gains or losses, and
the internal temperatures based on the building design. If heating and/or cooling system(s) are not specified,
any cooling/heating load will be displayed as “virtual energy.”
In addition, when absorption chiller powered by waste heat is selected as an energy efficiency measure the
heating and/or cooling energy is reduced depending on the load that the building has. The energy due to Pumps
is slightly increased due to the operation of the system.
Assumptions
The base case for air conditioning system efficiency is a COP of 2.66 and for heating system is assumed to be
electric with a COP of 2.66, as listed in the Key Assumptions for the Base Case in the Design section. The base
case can be over-written with the minimum COP required by local codes where they are in existence. With
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ENERGY EFFICIENCY MEASURES
regards of the heating system the fuel can be over-written changing the efficiency for the base case. If the key
assumptions are overwritten, then justification and documentation for local regulations must be provided. The
improved case COP for the Absorption Chiller system is 0.7 or 70% efficiency.
Compliance Guidance
In order to demonstrate compliance, the design team must describe the specified system and provide
documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:




Manufacturer’s data sheets for the absorption
chiller system specifying COP information and the
waste heat generator.
For systems including more than one chiller unit,
the design team must provide the average COP
calculation.
Mechanical and electrical layout drawings showing
the location of the external and internal units for all
floors.
Calculation to demonstrate that generators
capacity to deliver 100% of peak energy and that
waste heat needed to run the absorption chiller is
achieved.
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




As-built mechanical and electrical drawings with air
conditioning schematics for all floors and the
location of the waste heat generation.
Delivery notes showing that specified absorption
chillers have been delivered to the site.
Manufacturer’s data sheets for the absorption
chiller system specifying COP information and the
waste heat generator.
Photographs of installed external and internal air
conditioning units.
50
ENERGY EFFICIENCY MEASURES
HTE14 – RECOVERY OF WASTE HEAT FROM THE GENERATOR FOR SPACE
HEATING
Requirement Summary
This measure can be claimed if the power generator, providing 100% of building energy at the peak load, which
fuel is diesel or gas is running constantly and a recovery technology is installed to convert the waste heat in
space heating.
Intention
Recovering waste heat from power generators helps buildings to significantly reduce fossil fuel consumption,
lower operating costs, and pollutant emissions by providing useful heat for space heating. Hotels that use
energy for heating and that have a power generator as the main electricity source have the potential to benefit
from the application of heat recovery systems.
Potential Technologies/Strategies
In the context of buildings, heat recovery aim to collect and re-use the heat arising from process that would
otherwise be lost. Sometimes, the loss of this heat is intentional, such as in air conditioning, where the purpose
is to remove heat from a space. But in other cases the heat is lost in the exhaust fumes emitted by an electric
generator. The following image shows the different sources of waste heat and the uses of the recovered waste
heat:
Figure 3. Typical Sources of Waste Heat and Recovery Options 19
This waste heat can turn into useful space heating using a recovery technology such as the ones explain in the
table below:
19
Source: Heat is Power Association. Trade association of Waste Heat to Power (Not-for -Profit organization)
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ENERGY EFFICIENCY MEASURES
Table 23: Recovery technology options
Recovery technology
Thermal Energy Storage (TES)
Seasonal Energy Thermal Storage (STES)
Pre-heating
Cogeneration or Combined Heat and
Power (CHP) system
Recuperator
Heat Pipe exchanger20
Description
Buffer tank where Waste heat from different sources is stored and realized later to
reduce the heating load during night time
Similar to TES, but the heat is kept for longer periods of time, even months.
Usually, the heat is stored in a bigger area where a cluster of heat exchanger
equipped boreholes is surrounded by bedrock.
Simply waste heat can help to heat incoming water, air and objects before they
are heated to the desire temperature. This can happen in a heat exchanger, where
the waste heat is mixed with the income air/water to increase its temperature
before it enters in a boiler or heater.
It is a system that reduces the waste heat as it is used in the generation of power;
however some limitations arise from the engineering cost/efficiency of using small
temperature differences on the power generation.
This heat recovery device works through a heat exchanger that moves the flow of
hot and cold fluids.
In a container various vacuum filled tubes (heat pipes) are introduced to receive
the heat from exhaust air and transfer it to a cooler fluid.
Internally, the heat pipes contain a liquid that with the exhaust air evaporates and
transfer the heat out on the upper part of the tube, where the cool air/water is
passing through the container.
Relationship to Other Measures
EDGE calculates the heating load by taking account of the local climate, heat losses, and the internal
temperatures based on the building design. If heating system is not specified, any heating load will be displayed
as “virtual energy.”
In addition, when waste heat is recovered from the generator the heating load is reduced and therefore the
consumption is decreased due to ‘Heating Energy’. The energy due to Pumps is slightly increased due to the
operation of the system.
Assumptions
The base case for the fuel of the Electric generator is Diesel as listed in the Key Assumptions for the Base Case
in the Design section. The base case can be also changed to Natural Gas, if that is the main fuel available on
site. If the key assumption is overwritten, then justification and documentation for fuel availability must be
provided. Regardless of the fuel source, if the improved case uses this energy measure, it is assumed that the
generator is the main source of electricity and is running continuously.
Compliance Guidance
In order to demonstrate compliance, the design team must provide documentation to support the claims.
Design Stage
At the design stage the following must be used to demonstrate
compliance:




20
Manufacturer’s data sheets for electric generator specifying
hours of operation and coverage of the demand.
Manufacturer’s data sheets for the recovery technology
used.
Mechanical and electrical layout drawings showing the
location of the generator, the recovery technology and the
output for space heating system.
Calculation to demonstrate that generators capacity to
deliver 100% of peak energy and that waste heat
covers % of the demand for space heating as calculated in
EDGE software.
Post-Construction Stage
At the post-construction stage the following
must be used to demonstrate compliance:




As-built mechanical and electrical drawings
with the location of the generator, the
recovery technology and the output for
space heating system.
Delivery notes showing that specified
electric generator and the recovery
technology have been delivered to the site.
Manufacturer’s data sheets for electric
generator.
Photographs of installed external and
internal equipment related to the system.
Source: Heat is Power Association. Trade association of Waste Heat to Power (Not-for -Profit organization)
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ENERGY EFFICIENCY MEASURES
HTE15 – VARIABLE SPEED DRIVES ON THE FANS ON COOLING TOWERS
Requirement Summary
This measure can be claimed if the HVAC system requires a cooling tower(s) i.e. water cooled chillers are
installed, and only Variable Speed Driver (VSD) fan(s) are used in cooling tower(s).
Intention
By specifying VSD on the fans of cooling towers, energy consumption will be reduced, and therefore the utility
cost. Also the lifetime of the system components is increased and less maintenance requirements will be
needed.
Approach/Methodologies
In many cases, when cooling towers are part of the HVAC system, they just need to operate at the maximum
(peak) load at certain times, so their operation along the day or year is not continuous. Due to these intervals
installing VSD on the fans of cooling towers will reduce energy consumption, because the VSDs control and
regulate the fan speeds depending on the load of the HVAC system.
In order to claim this measure the design team must demonstrate that VSDs for all the fans of the cooling
towers are included within the HVAC system, which should be previously selected as Air Conditioning with Water
cooled chillers (HTE11).
Potential Technologies/Strategies
Some cooling systems, driven with water, have cooling towers, which are tubular structures that dispose the
unwanted heat. Within the cooling towers the warmer water is pumped from the chiller, which is then sprayed
out on the top of tower, then by evaporation as it falls and cools down, then it is send back to the chiller at a
lower temperature. In the meanwhile, the fans on the top are used to circulate the air within the tower; they
can be electronically control with the Variable Speed Drivers (VSD), which are a piece of equipment that
regulates the speed and the rotational force of the fan. VSD offer an improved system reliability and process
control, as well as result in energy savings.
Figure 4. Schematic of cooling tower and VSD system 21
21
Source: Image courtesy of Joliet Technologies, L.L.C. 2014 and Schneider Electric SE. 2014
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
When VSD for the fans of the cooling towers is selected as an energy efficiency measure, it is required that the
cooling system selected is Air Conditioning with Water cooled chiller (HTE11), this in order to show the savings.
The cooling energy will be reduced depending on the load that the building has.
Assumptions
The base case for air conditioning system efficiency is a COP of 2.66, referring to a standard Packaged Terminal
Air Conditioner (PTAC), as listed in the Key Assumptions for the Base Case in the Design section. Therefore as
the type of Air Conditioning, cooling towers are not part of the system and VSD are not part of the baseline. The
base case can be over-written with the minimum COP required by local codes where they are in existence. If the
key assumptions are overwritten, then justification and documentation for local regulations must be provided. If
the improve case is selected as Air Conditioning with Water Cooled chiller (HTE11) then cooling towers will be
part of the system and VSD can be selected. The assumption is that all fans in cooling towers will be provided
with VSDs.
Compliance Guidance
In order to demonstrate compliance, the design team must describe the specified system and provide
documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Mechanical and electrical layout drawings
highlighting the use of VSD in the fans of the
cooling towers.
Manufacturer’s data sheets for the air conditioning
with Water cooled chiller and cooling towers,
showing the specification of VSDs in the fans of the
cooling towers.
For systems including more than one cooling
tower, the design team must ensure that all fans
are provided with VSDs.
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Delivery notes showing that specified VSDs have
been delivered to the site along with the cooling
towers and the water cooled chillers.
Manufacturer’s data sheets for the air conditioning
with Water cooled chiller, showing the specification
of VSDs in the fans of the cooling towers.
Photographs of installed VSDs in the cooling
towers.
54
ENERGY EFFICIENCY MEASURES
HTE16 – VARIABLE SPEED DRIVES PUMPS
Requirement Summary
This measure can be claimed if the HVAC system has installed Variable Speed Drivers (VSD) pumps.
Intention
The aim is to encourage the project team to specify VSD pumps, as energy consumption will be reduced, and
therefore the utility cost. This enhances corporate reputation and helps to reduce the impact to climate change
Also the lifetime of the system components is increased and less maintenance requirements will be needed.
Approach/Methodologies
In many cases, the HVAC system just need to work at the maximum (peak) load at certain times, so their
operation along the day or year is not continuous. Due to these intervals installing VSD pumps of the
cooling/heating system will reduce energy consumption, because the VSDs control and regulate the speed of
the flow depending on the load of the HVAC system.
The following are the pros and cons of the VSDs:
Table 24: Benefits and limitations of the VSDs for pumps
Benefits
Improved Process Control:
Provide regulation functions that improve the whole system and protect the
other components of the system.
Limitations
A minimum speed of around 30% is permissible, as it is not
possible to reduce the flow all the way to zero.
Improved System Reliability
Simplified pipe systems (elimination of control valves & by-pass
lines)
Improved system lifetime:
Soft start & stop - Mechanical overload and peak pressures implied by on-off
systems are avoided
Reducing energy use, costs and maintenance
In order to claim this measure the design team must demonstrate that only VSDs pumps are installed. The
HVAC should be one of the systems that require pumps such as air or water cooled chillers, heat pumps, or
absorption chiller (HTE10 to HTE13), which should be previously assigned.
Potential Technologies/Strategies
There are various methods to regulate the speed of the flow in the pumps, to use the pump when the system is
in need, therefore reducing the energy consumption.
Variable Speed Drive (VSD) is an electronic equipment used to control the power into the motor of the pump, so
it is able to adjust the speed of the flow into a HVAC system, which is driven by the demand.
VSD offers a high degree of control and are extremely versatile. They are available as standalone device that is
connected to the motor of the pump except for motors below 15kW, which are embedded or integrated to the
motor.
Relationship to Other Measures
When VSD for the pumps is selected as an energy efficiency measure, it is required that the HVAC system
selected is Air or Water cooled chillers, heat pumps, or absorption chiller (HTE10 to HTE13), this in order to
show the savings. The energy due to pumps will be reduced depending on the load that the building has.
Assumptions
The base case for air conditioning system efficiency is a COP of 2.66 (Standard Packaged Terminal Air
Conditioner - PTAC) and for heating system is assumed to be electric with a COP of 2.66, as listed in the Key
Assumptions for the Base Case in the Design section. The base case can be over-written with HVAC systems
that comprise pumps, if required by local codes where they are in existence. With regards of the heating, the
systems included in the base case do not comprise pumps, so if the heating system is over-written, then no
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ENERGY EFFICIENCY MEASURES
change due to this measure will be shown. If the key assumptions are overwritten, then justification and
documentation for local regulations must be provided. If the improve case is selected as air or water cooled
chillers, heat pumps, or absorption chiller (HTE10 to HTE13) then pumps will be part of the system and VSD
(HTE16) can be selected. The assumption is that all pumps in the HVAC system will be provided with VSDs.
Compliance Guidance
In order to demonstrate compliance, the design team must describe the specified system and provide
documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Mechanical and electrical layout drawings showing
the whole HVAC system and highlighting the use of
VSD pumps.
Manufacturer’s data sheets VSD pumps.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Delivery notes showing that specified VSDs have
been delivered to the site.
Manufacturer’s data sheets for VSD pumps.
Photographs of installed VSD pumps.
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ENERGY EFFICIENCY MEASURES
HTE17 – SENSIBLE HEAT RECOVERY FROM EXHAUST AIR
Requirement Summary
This measure can be claimed if Sensible Heat Recovery device with at least 60% efficiency is installed in the
ventilation system to re-use the heat from the exhaust air.
Intention
Recovering sensible heat from exhaust air helps buildings to reduce fossil fuel consumption, and lower operating
costs by providing useful heat for space heating and in some cases for space cooling. Hotels that use energy for
heating or cooling with fresh air supply have the potential to benefit from the application of heat recovery
systems for ventilation.
Approach/Methodologies
When hotels include a HVAC system and the main load of the building is due to space heating/cooling, installing
sensible heat recovery to the ventilation system will reduce energy consumption, because the air is pre-heated
with the exhaust air or vice versa the temperature decreases with the exhaust air from the air conditioned
space (cooling mode).
In order to qualify the design team must demonstrate that the HVAC system has a ‘sensible heat recovery’
device on the fresh air supply system. No heat recovery system is included in the base case. EDGE uses
Temperature Transfer Efficiency (TTE) as the measure of efficiency, which might be quoted by manufacturers or
can be also calculated with the following formula:
Temperature Transfer Efficiency (TTE):
𝝁𝒕 =
Where:
𝑻𝟐−𝑻𝟏
𝑻𝟑−𝑻𝟏
μt = Temperature Transfer Efficiency (%)
T1 = Outside air temperature before heat exchanger (ºC)
T2 = Air temperature after heat exchanger (ºC)
T3 = Exhaust air temperature before heat exchanger (ºC)
Potential Technologies/Strategies
In the context of buildings, heat recovery aims to collect and re-use the heat arising from process that would
otherwise be lost. In this measure in particular, it involves transfer of energy between an exhaust airstream
that preheats (winter mode) or precool (summer mode) the supply airstream. As air contains moisture, the heat
contained within the air can be sensible heat (affects the temperature) or latent heat (includes water vapor).
Some energy recovery devices transfer both sensible and latent heat also called ‘total heat recovery’, and some
only transfer sensible heat, which is the concern of this measure (HTE17).
Sensible Heat Recovery occurs when the temperature of the cooler air stream increases and the temperature of
the warmer air stream decreases or vice versa. Moisture is not transferred unless condensation occurs.
In some areas of the hotels where condensation is expected, such as pools, spas and restaurants, this
technology is ideal as the materials are anti-corrosive. It is also convenient for light ventilation systems as it
offers low pressure drops.
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
Sensible heat is recovered from the exhaust air, the heating load is reduced and therefore the consumption is
decreased due to ‘Heating Energy’. The same principle happens to the cooling load if the building uses
predominately air conditioning, and then the reduction is in ‘Cooling Energy’. However, in climates where both
heating and cooling are used, then the savings are shown in the ‘heating energy’, but the ‘cooling energy’
increases due to some heat is trapped during midseason. The energy due to ‘Fans’ is slightly decreased as less
air is moved.
Assumptions
The HVAC systems included in the base case do not comprise heat recovery systems. The improve case is
assumed to have a Sensible heat recovery device with a Temperature Transfer Efficiency (TTE) of at least 60%.
If actual TTE value is higher or lower thank 60%, the actual values must be entered into the tool. It is also
assumed that at least 75% of all exhaust air in the building is being passed through the heat recovery system.
Compliance Guidance
In order to demonstrate compliance, the design team must provide documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:




Manufacturer’s data sheets for sensible heat
recovery device specifying Temperature Transfer
Efficiency.
Mechanical and electrical layout drawings showing
the location of the heat recovery technology and
indicating % of total air passing through the heat
recovery system.
.
In case, manufacture’ data do not specify TTE,
calculation to demonstrate efficiency should be
undertaken.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




As-built mechanical and electrical drawings with
the location of recovery technology, if changed
from design.
Delivery notes showing that specified recovery
technology have been delivered to the site.
Manufacturer’s data sheets for the Sensible Heat
recovery technology used specifying efficiency
(TTE) if changed from design.
Photographs of installed heat recovery system.
58
ENERGY EFFICIENCY MEASURES
HTE18 – HIGH EFFICIENCY CONDENSING BOILER FOR SPACE HEATING
Requirement Summary
This measure can be claimed if the boiler used for delivering space heating is a gas condensing boiler with
annual fuel utilization efficiency greater than the base case, as set out in the Key Assumptions for the Base
Case in the Design section. By default the base case system efficiency is 82% if Gas is selected as the heating
fuel.
Intention
The specification of a condensing boiler for space heating reduces the energy required to satisfy the heating
load for the building, if the fuel selected for heating is gas. Condensing boilers can have efficiency up to 97%.
Approach/Methodologies
In order to qualify, the condensing boiler must be able to demonstrate efficiency greater than the base case of
82%. There are different methodologies for calculating the efficiency of a condensing boiler. Manufacturers
might quote the gross efficiency, net efficiency, seasonal efficiency, or the annual fuel utilization efficiency
(AFUE), each of which uses a different methodology to calculate the percentage.
EDGE uses AFUE as the measure of efficiency as it provides the most consistent methodology. AFUE is
calculated by comparing the thermal energy output to the calorific value of the fuel used. AFUE data is available
from the Energy Star website at http://www.energystar.gov/productfinder/product/certified-boilers/results.
Modular systems usually use multiple boilers of the same size and type. However, where boilers with different
efficiency ratings are specified the weighted average efficiency should be calculated. The weighted efficiency
takes into account the size of the boilers and the expected run time.
Potential Technologies/Strategies
An efficient boiler is one that turns as much of its fuel into useful energy with as little as possible wasted. The
boilers likely to achieve the highest level of efficiency are condensing boilers. They utilize the latent heat in the
waste gases’ water vapor which is generated by the combustion process. Condensing boilers have a larger heat
exchanger that recovers more heat and send cooler gases up the flue, which condensate water vapor and more
energy is recovered from the condensing vapor. Then, the water or ‘condensate’ generated is removed through
the drain or the flue. The types of condensing boilers available in the market are as follows:
Table 25: Types of Condensing Boiler
Type / method
Combination boilers or
'Combi'
System boilers
Description





Heat-only boilers


Modulated control boilers


Heats water instantaneously on demand
No need for a loft tank or storage cylinder
Good water pressure, as water is directly
from the mains
Economical to run
Designed to generate space heating and hot
water, the last one is stored in a separate
hot water storage cylinder.
Provide both space heating and hot water
Hot water storage cylinder and cold water
top up tanks are required
New generation
more efficient as per the modulated controls
To achieve the best possible results care should be taken not to oversize the boiler, since maximum levels of
efficiency are achieved at a full load. In larger buildings with a centralized plant, like a hotel, a modular system
made up of an array of smaller boilers may be appropriate. Smaller boilers can be used so that when the
system is under partial load, individual boilers within the array can still operate at full load.
To minimize the cost of a boiler installation, the heat loads should be minimized before sizing the system.
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
The heat demand that the boiler is sized to supply is affected by the balance between the heat gains and heat
losses. Heat losses should be minimized at the cost of fabric improvements implemented during the initial
construction is typically lower than the cost of a larger plant.
If this measure is selected the main fuel for space heating must be selected as ‘Natural Gas’ in the key
assumptions for base case in the Design page. Only ‘Heating energy’ is reduced with this measure.
Assumptions
The base case for the efficiency of the space-heating boiler is 82% and the improved case is 90%. The base
case is assumed to use Electricity as the fuel for heating, if this measure is selected, main fuel has to change to
‘Natural Gas’.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Manufacturer’s data sheet for the condensing
boiler/s specified.
System schematics showing the brand and model
of boiler/s.
If multiple condensing boilers with different
efficiencies are specified, then the calculation of
average weighted efficiency must be provided.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




Updated system schematics.
Photographs of the installed condensing boilers.
Purchase receipts and delivery notes for the
condensing boilers.
Manufacturer’s data sheet for the condensing
boiler/s purchased.

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ENERGY EFFICIENCY MEASURES
HTE19 – HIGH EFFICIENCY BOILER FOR WATER HEATING
Requirement Summary
This measure can be claimed if the boiler used for delivering hot water heating has annual fuel utilization
efficiency greater than the base case, as set out in the Key Assumptions for the Base Case in the Design
section. By default the base case is 80%.
Intention
The specification of a highly efficient boiler for water heating reduces the energy required to satisfy the hot
water demand for the building.
Approach/Methodologies
In order to qualify, the high efficiency boiler must be able to demonstrate efficiency greater than the base case
of 80%. There are different methodologies for calculating the efficiency of a boiler. Manufacturers might quote
the gross efficiency, net efficiency, seasonal efficiency, or the annual fuel utilization efficiency (AFUE), each of
which uses a different methodology to calculate the percentage.
EDGE uses AFUE as the measure of efficiency as it provides the most consistent methodology. AFUE is
calculated by comparing the thermal energy output to the calorific value of the fuel used. AFUE data is available
from the Energy Star website at http://www.energystar.gov/productfinder/product/certified-boilers/results.
Modular systems usually use multiple boilers of the same size and type. However, where boilers with different
efficiency ratings are specified the weighted average efficiency should be calculated. The weighted efficiency
takes into account the size of the boilers and the expected run time.
Potential Technologies/Strategies
The most efficient boilers are maximum 97% efficiency, because energy (heat) is lost via the flue gases and
through the main body of the boiler itself; also lack of maintenance can reduce efficiency of the boiler.
The following table shows a set of solutions related to hot water boilers for hotels:
Table 26: Types of High Efficiency Hot Water Boilers22
Type
Condensing boilers
Combi Boiler
Low temperature hot water
(LTHW) boilers
High-efficiency boilers
“Staged” multiple-boiler
system
Modular boiler systems
22
23
Description
The only boilers likely to achieve efficiency level of at least 90%. They extract the latent heat
from the waste gases’ water vapor that is generated by the combustion process. To minimize
the cost of a boiler installation, the hot water demand should be minimized before sizing the
system.
This is a type of condensing boiler that provides both heating and hot water without needing a
separate tank. The combi boiler is most suited to small hotels or when the hotel is zoned in
various small units.23
Produce hot water at around 90ºC, which is then distributed via pipework to a hot water
storage tanks. These boilers are commonly run by Natural Gas.
They are more efficient because they have lower water contents, larger heat exchanger
surface areas and greater insulation of the boiler shell. They are suitable to applications where
a higher water temperature is required, such as kitchens, laundry and showers.
Reduces the amount of time in which a boiler is running at less than peak load. This is because
in the staged system, only few boilers run depending on the demand. So, in the mornings
when guests are having showers more boilers are in use while during the day only the boilers
to cover a small demand will be active.
Series of boilers linked together to meet a different demands, reason why they are suitable to
buildings or processes with a significant variable hot water/heating demand.
The Carbon Trust. Low temperature hot water boilers. UK: March 2012.
http://www.glow-worm.co.uk/boilers-3/your-boiler-guide/how-does-your-boiler-work/
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
The hot water demand that the boiler is sized to supply is affected by the rate of hot water use. Hot water use
should be minimized first by selecting low-flow taps in washbasins and low-flow showerheads.
If this measure is selected the main fuel for hot water must be selected as ‘Natural Gas’ in the key assumptions
for base case on the Design page. This measure reduces both ‘Water Heating’ and ‘Other’ due to pumping water
in the system.
Assumptions
The base case for the efficiency of the hot water boiler is 80% and the improved case is 90%. The default is
assumed to use Electricity as the fuel for hot water, if this measure is selected, main fuel has to be changed to
‘Natural Gas’.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Manufacturer’s data sheet for the boiler/s specified.
System schematics showing the brand and model
of boiler/s.
If multiple boilers with different efficiencies are
specified, then the calculation of average weighted
efficiency must be provided.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




Updated system schematics.
Photographs of the installed boilers.
Purchase receipts and delivery notes for the
boilers.
Manufacturer’s data sheet for the boiler/s
purchased.
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ENERGY EFFICIENCY MEASURES
HTE20 – VARIABLE SPEED HOODS WITH AUTOMATED FAN CONTROLS
Requirement Summary
This measure can be claimed if the exhaust hoods of the kitchen have installed Variable Speed Drivers (VSD) to
their fan(s).
Intention
By specifying VSD on the fans of exhaust hoods in the kitchens, energy consumption will be reduced, and
therefore the utility cost. Also the lifetime of the system components is increased and less maintenance
requirements will be needed.
Approach/Methodologies
Standard exhaust hoods in commercial kitchens operate at the maximum (peak) load, however that peak
ventilation is not always required. Smart controlled hoods have installed VSDs on the fans, which are controlled
by a temperature sensor, therefore reducing energy consumption between 20% and 50% (see figure below),
because the VSDs control and regulate the fan speeds depending on the temperature of the cooking surface.
Lowering fan speed reduces noise levels as well as maintenance costs, while the life of kitchen equipment could
be extended.
In order to claim this measure the design team must demonstrate that VSDs with temperature control are
installed within the exhaust hoods of the kitchen.
Figure 5. Savings with use of VSD on kitchen hoods 24
Potential Technologies/Strategies
According to the US Environmental Protection Agency (EPA) kitchens in commercial premises consume 2.5
times more energy than any other commercial space, from which only 40% is used in food preparation and
storage25 the majority of the energy is used in ventilation. Kitchens in hotels mostly have grills, ovens and
fryers, which requires high levels of ventilation and therefore consume large amount of electricity. In many
cases this is because the fans in the kitchen hoods are running constantly and at maximum speed regardless of
the air that needed to be removed. Lowering the speed of fans and controlling the time of use with sensors (air
temperature) will result in energy reduction.
The fans can be electronically control with the Variable Speed Drivers (VSD), which are a piece of equipment
that regulates the speed of the fan according to air temperature, which is detected by a sensor installed inside
the exhaust hood. It can determine if the cooking surface temperature rises, therefore the fan speed increases
to compensate, but if the air is cooler, then, the fan runs slower. VSD offer an improved system reliability and
process control, as well as result in energy savings.
24
Source: image courtesy of :http://www2.schneider-electric.com/sites/corporate/en/customers/contractors/energy-efficiencysolution-for-buildings/hvac_control_regulate_kitchen_exhaust.page
25
Carbon Trust UK quoted by International Tourist Partnership - http://www.greenhotelier.org/our-themes/energy-efficiency-inthe-kitchen/
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
Energy reduction due to kitchen equipment is expected by automated control hoods which will be reflected in
the 'Catering Energy' portion of the energy chart, and its contribution is purely related to energy.
Assumptions
The base case assumes conventional exhaust hoods in kitchens, while the improved case assumes that all the
exhaust hoods are provided with VSDs that control the fan speed according to the temperature at the cooking
surface.
Compliance Guidance
In order to demonstrate compliance, the design team must provide documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Electric drawings/specifications of automated control
hood including make and model of the VSD control.
Manufacturer’s specification of the automated control
hood.
For systems including more than one exhaust hood,
the design team must ensure that all fans are
provided with VSDs.
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Post-Construction Stage
At the post-construction stage the following must be used
to demonstrate compliance:



As-built electrical drawings detailing the automated
control hood installed
Photographs of installed VSDs in the exhaust hoods of
the kitchen.
Purchase receipt for the automated control hood.
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ENERGY EFFICIENCY MEASURES
HTE21 – PREHEAT WATER USING WASTE HEAT FROM THE GENERATOR
Requirement Summary
This measure can be claimed if the power generator, which fuel is diesel or gas, produce steam and is running
constantly and a recovery technology is installed to use the waste heat to preheat the water that will be input
into the main hot water system of the hotel.
Intention
Recovering waste heat from power generators helps buildings to significantly reduce fossil fuel consumption,
lower operating costs, and pollutant emissions by preheating the water that will be used in bathrooms, laundry
and kitchens as part of the hot water system. Hotels that use energy for hot water and that have a power
generator as the main electricity source have the potential to benefit from the application of heat recovery
systems.
Approach/Methodologies
Having a recovery system that uses the waste heat for the hot water production can lead to benefits such as
low maintenance, quiet operation and high availability. As well as reducing the energy costs and the carbon
emissions, as less fuel is consumed.
Potential Technologies/Strategies
In the context of buildings, heat recovery aim to collect and re-use the heat arising from process that would
otherwise be lost. Sometimes, the loss of this heat is intentional, such as in air conditioning, where the purpose
is to remove heat from a space. But in other cases the heat is lost in the exhaust fumes emitted by an electric
generator. This waste heat can turn into useful hot water generation or pre-heat the water feeding the boiler
using a recovery technology.
Relationship to Other Measures
In addition, when waste heat is recovered from the generator the load due to hot water is reduced and
therefore the consumption is decreased due to ‘Water Heating’.
Assumptions
The default for the fuel of the Electric generator is Diesel as listed in the Key Assumptions for the Base Case in
the Design section. The fuel can be also changed to Natural Gas, if that is the main fuel available on site. If the
key assumption is overwritten, then justification and documentation for fuel availability must be provided.
Regardless of the fuel source, if the improved case uses this energy measure, it is assumed that the generator
is the main source of electricity and is running continuously and that the hot water demand is covered by the
recovery of the waste heat.
Compliance Guidance
In order to demonstrate compliance, the design team must provide documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:




Manufacturer’s data sheets for generator specifying
hours of operation and coverage of the demand.
Manufacturer’s data sheets for the recovery
technology used.
Mechanical and electrical layout drawings showing
the location of the generator, the recovery
technology and the output for the water heating
system.
Calculation to demonstrate that waste heat
covers % of the demand for hot water as
calculated by EDGE software.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




As-built mechanical and electrical drawings with
the location of the generator, the recovery
technology and the output for hot water.
Delivery notes and purchase receipts showing that
specified generator and the recovery technology
have been delivered to the site.
Manufacturer’s data sheets for generator specifying
hours of operation and coverage of the demand.
Photographs of installed external and internal
equipment related to the system.
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ENERGY EFFICIENCY MEASURES
HTE22 – HEAT RECOVERY FROM GREY WATER
Requirement Summary
This measure can be claimed if heat recovery device with at least 30% efficiency is installed in the hot water
system to re-use the heat from the grey water.
Intention
Recovering heat from the grey water, drain water from showers, kitchens, spa area, laundry, etc. helps to
reduce fossil fuel consumption of buildings, lower operating costs , and pollutant emissions by preheating the
water that will be used later on in bathrooms, laundry and kitchens as part of the hot water system. Hotels that
use energy for hot water have the potential to benefit from the application of heat recovery systems.
Approach/Methodologies
Hotels can benefit of the Grey Water heat recovery, as it can save energy and increase the capacity of
undersized water heaters. In order to qualify the design team must demonstrate that the Hot water system has
a ‘heat recovery’ device. EDGE uses efficiency of 30% for improved case, which should be quoted by
manufacturers.
Potential Technologies/Strategies
In the context of buildings, heat recovery aims to collect and re-use the heat arising from process that would
otherwise be lost. In this measure in particular, it involves transfer of energy between hot grey water coming
from showers, bath tubs, sinks, dishwashers, etc and the incoming cold potable water. So, the heat from water
already used is employed to preheat cold water entering the boiler, minimizing water heating. There are various
commercial solutions available for grey water heat recovery that ranges from non-storage systems (shower only
recovery) to centralize heat recovery, which connects more equipment and augment the possibilities for use of
the recovered energy. The following table shows some of the solutions:
Table 27: Grey Water Heat Recovery Solutions26
Types
Spiral design
(Non Storage)
26
Description
Hot water runs through a series of narrow spirals, in
which it is forced to spin alongside the walls of the heat
recovery pipe. The cold water then comes as a counter
flow in a spiral pipe swirled around the outside. This
design requires small gaps (2cm) to avoid plugging.
It is commonly used in residential and small hotels.
Instead of spiral system tubular heat exchanger or
rectangular heat exchanger systems can be used.
Sources: US department of energy and shower save
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ENERGY EFFICIENCY MEASURES
Accumulation
tank
(centralized)
Grey water from different sources is accumulated in a
tank, which has an electrical coil (close loop) that
transfers the heat to the cold water passing through the
grey-water heat recovery unit outside the tank.
parallel heat
exchanger
(centralized)
This is ideal for larger hotels, as it collects the grey water
in one pipe that passes through the heat exchanger. It is
similar to spiral design but used centrally rather than in
each unit.
Relationship to Other Measures
The hot water demand that the boiler is sized to supply is affected by the rate of hot water use. Hot water use
should be minimized first by selecting low-flow taps in washbasins and low-flow showerheads.
This measure reduces both ‘Water Heating’ and ‘Other’ due to pumping water in the system.
Assumptions
The base case assumes no heat recovery from grey water, while the improved case assumes that all the
sources of hot water except laundry have a heat recovery system with 30% efficiency.
Compliance Guidance
In order to demonstrate compliance, the design team must provide documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Manufacturer’s data sheets for grey water heat
recovery device specifying recovery technology
used and its efficiency (%).
Hydraulic layout drawings showing the location of
the recovery technology.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




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As-built hydraulic drawings with the location of
recovery technology if changed from design.
Delivery notes and purchase receipts showing that
specified recovery technology have been delivered to
the site.
Manufacturer’s data sheets for grey water heat
recovery device specifying recovery technology used
and its efficiency (%).
Photographs of installed equipment related to the
system.
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ENERGY EFFICIENCY MEASURES
HTE23 – HEAT RECOVERY FROM LAUNDRY WASTE WATER
Requirement Summary
This measure can be claimed if heat recovery device with at least 30% efficiency is installed in the hot water
system to re-use the heat from the grey water of the laundry.
Intention
Recovering heat from the grey water of the laundry helps to reduce fossil fuel consumption of buildings, lower
operating costs , and pollutant emissions by preheating the water that will be used in bathrooms, laundry and
kitchens as part of the hot water system. Hotels that use energy for hot water have the potential to benefit
from the application of heat recovery systems.
Approach/Methodologies
Hotels can benefit of the Grey Water heat recovery of Laundry, as it can save energy and increase the capacity
of undersized water heaters.
In order to qualify the design team must demonstrate that the hot water system has a ‘heat recovery’ device
installed on the grey water coming from the laundry, which efficiency must be greater than the base case (no
heat recovery is included in the base case). EDGE uses Efficiency (%), which should be quoted by
manufacturers.
Potential Technologies/Strategies
In the context of buildings, heat recovery aims to collect and re-use the heat arising from process that would
otherwise be lost. In this measure in particular, it involves transfer of energy between hot grey water coming
from the laundry area (washing machines) and the incoming cold potable water. So, the heat from water
already used in laundry is employed to preheat cold water entering the boiler, minimizing water heating. There
are various commercial solutions available for grey water heat recovery that ranges from non-storage systems
to centralize heat recovery, which connects more equipment and augment the possibilities for use of the
recovered energy.
Relationship to Other Measures
The hot water demand that the boiler is sized to supply is affected by the rate of hot water use. Hot water use
should be minimized first by selecting low-flow taps in washbasins and low-flow showerheads. This measure
reduces both ‘Water Heating’ and ‘Other’ due to pumping water in the system. This measure can be used along
with HTE22 – Heat recovery from grey water.
Assumptions
The base case assumes no heat recovery from grey water, while the improved case assumes that the hot water
coming from laundry area have a heat recovery system with 30% efficiency.
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ENERGY EFFICIENCY MEASURES
Compliance Guidance
In order to demonstrate compliance, the design team must provide documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Manufacturer’s data sheets for grey water heat
recovery device specifying recovery technology
used and its efficiency (%).
Hydraulic layout drawings showing the location of
the recovery technology installed in the laundry
area.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




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As-built hydraulic drawings with the location of
recovery technology installed in the laundry area if
changed from design stage.
Delivery notes and purchase receipts showing that
specified recovery technology have been delivered to
the site.
Manufacturer’s data sheets for grey water heat
recovery device specifying recovery technology used
and its efficiency (%).
Photographs of installed equipment related to the
system.
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ENERGY EFFICIENCY MEASURES
HTE24 – ENERGY – SAVING LIGHT BULBS – INTERNAL SPACES
Requirement Summary
This measure can be claimed if the light bulbs in all internal spaces (including guest rooms, bathrooms,
conference/banquet rooms, corridors, etc.) are either compact fluorescent (CFL), LED, or T5 type.
Intention
The specification of CFL, LED, or T5 lamps reduces the building’s energy use for lighting. Due to the improved
energy efficiency, heat gains are lowered, which in turn reduces cooling requirements. As the service life of
these types of bulbs is generally higher than that of incandescent bulbs, maintenance costs are also reduced.
WTO (2011)27 indicates that efficient lighting have a load potential saving up to 75% and a reduced payback of
1 to 3 years, Table 28 shows the potential savings when using CFLs instead of incandescent light bulbs.
Approach/Methodologies
EDGE uses no specific measure of efficacy, so the design team only needs to demonstrate that CFL, LED, or T5
lamps have been specified. Both fluorescent (CFL and T5) and LED bulbs are available with various performance
specifications.
The measure of lighting efficacy used in the industry is lumens per watt, which is the ratio of visible light output
to total power output (luminous flux/radiant flux). A lumen is the amount of visible light produced by a bulb.
The radiant flux is equal to the power input for the bulb, i.e. a 40W light bulb has a radiant flux (total power
output) of 40W.
EDGE does not interfere with lighting quality, lux levels, or lighting layout. This should be handled by the
lighting designer using local or international lighting design code requirements. EDGE lighting excludes safety
and security lighting design.
Potential Technologies/Strategies
The following table explains the different technologies considered energy saving light bulbs:
Table 28: Description of technologies (lamp types)
Lamp Type
Description
Compact fluorescent
lamps (CFLs)
CFLs are available for most light fittings as a direct replacement for incandescent bulbs. CFLs use a
fluorescent tube that has been folded into the shape of the incandescent bulb they have been
designed to replace. In comparison to incandescent bulbs, CFLs can last as much as 15 times longer.
It should be noted that the service life can be reduced by frequent switching, so CFLs are not always
appropriate where lights will be turned on and off frequently. CFLs use only a fraction of the energy of
their incandescent alternatives and therefore produce less heat.
As with normal fluorescent lamps, CFLs require ballasts in order to operate. Older lamps use magnetic
ballasts, but these have largely been replaced with electronic ballasts that operate at a high
frequency. Although the efficacy is not affected, electronic ballasts have reduced warm-up time and
flickering, which was a criticism of the earlier lamps.
Light emitting diode
(LED)
LED technology is evolving quickly and, as with CFLs, there are LED lamps available for most light
fittings. While most available LED lamps do not achieve efficacy levels as high as CFLs, the theoretical
maximum far exceeds them. The service life of LED lamps can be as much as two to three times the
longest life of any available compact fluorescent lamp, and is not affected by frequent on/off cycles.
T5 Lamps
The name of these fluorescent tubes refers to their shape (tubular) and diameter (measured in 1/8s
of an inch). T5s have a miniature G5 bi-pin base with 5mm spacing, while T8s and T12s have a G13
bi-pin base with 13mm spacing. Although T8/T12 to T5 conversion kits are available, dedicated T5
luminaires should be specified in new construction projects, as using ballasts designed for T8s and
T12s could reduce the service life of T5s.
While the efficacy of T5s is higher than T8s (T5s can achieve efficacy as high as 100 lumens/watt)
they can have a slightly shorter service life than T8s.
27
World Tourism Organization - Hotel Energy Solutions. Key Energy Efficiency Technologies Database for SME Hotels. Hotel
Energy Solutions project publications. 2011
International Finance Corporation
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ENERGY EFFICIENCY MEASURES
Although the efficacy of different manufacturers’ bulbs will differ greatly,
Table 29 gives an approximate range of efficacies that can be expected for different bulb technologies.
Table 29: Typical range of efficacies for different lamp types28
Lamp Type
Typical Range of Efficacy
(Lumens/Watt)
Incandescent – Tungsten Filament
Incandescent – Tungsten Halogen
Compact Fluorescent
Tubular Fluorescent
Low Pressure Sodium
High Pressure Sodium
High Pressure Metal Halide
8-12
12-24
50-85
65–100
100–190
65–140
70–100
Relationship to Other Measures
Using more efficient bulbs reduces the heat gain from lighting, thereby reducing cooling loads. A better daylight
design can reduce the need for artificial lighting during the day light hours.
Assumptions
The default assumption is that tungsten filament lamps are specified throughout, and the default lighting
density required is based on the typical efficacy of tungsten (14 lumens/watt). The lighting load (in Watts/m²)
for each area in both cases (baseline and improved) is as follows:
Table 30: Assumed lighting loads for the base case and improved case
Internal Lighting
Guest rooms
Toilet-Guest Room
Front of house
Corridor
Conference /Banquet
Base Case [LPD:
W/m²]
Improved Case [LPD:
W/m²]
11.3
9.7
12.3
10.8
14.0
2.9
2.9
6.2
10.8
14.0
Compliance Guidance
Design Stage
At the design stage one or all of the following must be
used to demonstrate compliance:


Lighting schedule listing type and number of bulbs
specified.
Electrical layout drawings showing the location and
type of all installed bulbs.
Post-Construction Stage
At the post-construction stage one or all of the
following must be used to demonstrate compliance:



28
Photographs of the lighting installation. It is not
necessary to take photos of every single
installed lamp, but the auditor must be
convinced that a reasonable proportion has been
checked and verified.
As-built electrical drawings with the lighting
layout if changed from design.
Purchase receipts and delivery notes for lamps
Source: Energy efficiency in lighting – an overview, GIR092, Action Energy, 2003
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ENERGY EFFICIENCY MEASURES
HTE25 – ENERGY – SAVING LIGHT BULBS – EXTERNAL SPACES
Requirement Summary
This measure can be claimed if the light bulbs in common outdoor spaces, such as outdoor garden, are either
compact fluorescent (CFL), LED, or T5 type.
Intention
The specification of CFL, LED, or T5 lamps reduces the building’s energy use for lighting. As the service life of
these types of bulbs is generally higher than that of incandescent bulbs, maintenance costs are also reduced.
And it is also one of the easiest ways to reduce energy consumption in a hotel, as lighting account for a large
portion of energy use.
Approach/Methodologies
EDGE uses no specific measure of efficacy, so the design team only needs to demonstrate that CFL, LED, or T5
lamps have been specified for external spaces. Both fluorescent (CFL and T5) and LED bulbs are available with
various performance specifications. The key indicators are the color rendering index (CRI), color temperature
(in Kelvin), service life, and efficacy (lumens/watt). The CRI is a good indication of the quality of the light
produced, as the higher the CRI the better the colors will be rendered. As color temperature is more subjective,
the appropriate level will depend on the application.
EDGE does not interfere with lighting quality, lux levels, or lighting layout. This should be handled by the
lighting designer using local or international lighting design code requirements. EDGE lighting excludes safety
and security lighting design.
Potential Technologies/Strategies
The following table explains the different technologies considered energy saving light bulbs, which can be also
solar-powered for even higher savings:
Table 31: Description of technologies (lamp types)
Lamp Type
Description
Compact fluorescent
lamps (CFLs)
CFLs are available for most light fittings as a direct replacement for incandescent bulbs. CFLs use a
fluorescent tube that has been folded into the shape of the incandescent bulb they have been
designed to replace. In comparison to incandescent bulbs, CFLs can last as much as 15 times longer.
It should be noted that the service life can be reduced by frequent switching, so CFLs are not always
appropriate where lights will be turned on and off frequently, such as external security lights linked to
movement detectors. CFLs use only a fraction of the energy of their incandescent alternatives and
therefore produce less heat.
As with normal fluorescent lamps, CFLs require ballasts in order to operate. Older lamps use magnetic
ballasts, but these have largely been replaced with electronic ballasts that operate at a high
frequency. Although the efficacy is not affected, electronic ballasts have reduced warm-up time and
flickering, which was a criticism of the earlier lamps.
Light emitting diode
(LED)
LED technology is evolving quickly and, as with CFLs, there are LED lamps available for most light
fittings. While most available LED lamps do not achieve efficacy levels as high as CFLs, the theoretical
maximum far exceeds them. The service life of LED lamps can be as much as two to three times the
longest life of any available compact fluorescent lamp, and is not affected by frequent on/off cycles.
T5 Lamps
The name of these fluorescent tubes refers to their shape (tubular) and diameter (measured in 1/8s
of an inch). T5s have a miniature G5 bi-pin base with 5mm spacing, while T8s and T12s have a G13
bi-pin base with 13mm spacing. Although T8/T12 to T5 conversion kits are available, dedicated T5
luminaires should be specified in new construction projects, as using ballasts designed for T8s and
T12s could reduce the service life of T5s.
While the efficacy of T5s is higher than T8s (T5s can achieve efficacy as high as 100 lumens/watt)
they can have a slightly shorter service life than T8s.
Relationship to Other Measures
The contribution that the measure makes to the overall performance is not affected by any other measure.
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ENERGY EFFICIENCY MEASURES
Assumptions
By default, EDGE assumes a standard mix of lamp types used in communal outdoor areas. The lighting load (in
Watts/m²) for each area is as follows:
Table 32: Assumed lighting loads for the base case and improved case.
External Lighting [LPD W/m²]
Base Case
Improved Case
External
1.5
0.8
Car Parking
2.2
1.8
Compliance Guidance
Design Stage
At the design stage one or all of the following must be
used to demonstrate compliance:


Lighting schedule listing type and number of
bulbs specified.
Electrical layout drawings showing the location
and type of all installed bulbs.
Post-Construction Stage
At the post-construction stage one or all of the
following must be used to demonstrate compliance:



International Finance Corporation
Photographs of the lighting installation. It is not
necessary to take photos of every single
installed lamp, but the auditor must be
convinced that a reasonable proportion has been
checked and verified.
As-built electrical drawings with the lighting
layout if changed from design.
Purchase receipts and delivery notes for lamps
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ENERGY EFFICIENCY MEASURES
HTE26 – ENERGY – SAVING LIGHT BULBS – BACK-OF-HOUSE
Requirement Summary
This measure can be claimed if the light bulbs in the hotel's back house (including kitchens, laundry, health spa,
storage area, etc.) are either compact fluorescent (CFL), LED, or T5 type.
Intention
The specification of CFL, LED, or T5 lamps reduces the building’s energy use for lighting. Due to the improved
energy efficiency, heat gains are lowered, which in turn reduces cooling requirements. As the service life of
these types of bulbs is generally higher than that of incandescent bulbs, maintenance costs are also reduced.
WTO (2011)29 indicates that efficient lighting have a load potential saving up to 75% and a reduced payback of
1 to 3 years, Table 33 shows the potential savings when using CFLs instead of incandescent light bulbs.
Approach/Methodologies
EDGE uses no specific measure of efficacy, so the design team only needs to demonstrate that CFL, LED, or T5
lamps have been specified. Both fluorescent (CFL and T5) and LED bulbs are available with various performance
specifications.
The measure of lighting efficacy used in the industry is lumens per watt, which is the ratio of visible light output
to total power output (luminous flux/radiant flux). A lumen is the amount of visible light produced by a bulb.
The radiant flux is equal to the power input for the bulb, i.e. a 40W light bulb has a radiant flux (total power
output) of 40W.
EDGE does not interfere with lighting quality, lux levels, or lighting layout. This should be handled by the
lighting designer using local or international lighting design code requirements. EDGE lighting excludes safety
and security lighting design.
Potential Technologies/Strategies
The following table explains the different technologies considered energy saving light bulbs:
Table 33: Description of technologies (lamp types)
Lamp Type
Description
Compact fluorescent
lamps (CFLs)
CFLs are available for most light fittings as a direct replacement for incandescent bulbs. CFLs use a
fluorescent tube that has been folded into the shape of the incandescent bulb they have been
designed to replace. In comparison to incandescent bulbs, CFLs can last as much as 15 times longer.
It should be noted that the service life can be reduced by frequent switching, so CFLs are not always
appropriate where lights will be turned on and off frequently. CFLs use only a fraction of the energy of
their incandescent alternatives and therefore produce less heat.
As with normal fluorescent lamps, CFLs require ballasts in order to operate. Older lamps use magnetic
ballasts, but these have largely been replaced with electronic ballasts that operate at a high
frequency. Although the efficacy is not affected, electronic ballasts have reduced warm-up time and
flickering, which was a criticism of the earlier lamps.
Light emitting diode
(LED)
LED technology is evolving quickly and, as with CFLs, there are LED lamps available for most light
fittings. While most available LED lamps do not achieve efficacy levels as high as CFLs, the theoretical
maximum far exceeds them. The service life of LED lamps can be as much as two to three times the
longest life of any available compact fluorescent lamp, and is not affected by frequent on/off cycles.
T5 Lamps
The name of these fluorescent tubes refers to their shape (tubular) and diameter (measured in 1/8s
of an inch). T5s have a miniature G5 bi-pin base with 5mm spacing, while T8s and T12s have a G13
bi-pin base with 13mm spacing. Although T8/T12 to T5 conversion kits are available, dedicated T5
luminaires should be specified in new construction projects, as using ballasts designed for T8s and
T12s could reduce the service life of T5s.
While the efficacy of T5s is higher than T8s (T5s can achieve efficacy as high as 100 lumens/watt)
they can have a slightly shorter service life than T8s.
29
World Tourism Organization - Hotel Energy Solutions. Key Energy Efficiency Technologies Database for SME Hotels. Hotel
Energy Solutions project publications. 2011
International Finance Corporation
74
ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
Using more efficient bulbs reduces the heat gain from lighting, thereby reducing cooling loads.
Assumptions
The default assumption is that tungsten filament lamps are specified throughout, and the default lighting
density required is based on the typical efficacy of tungsten (14 lumens/watt). The lighting load (in Watts/m²)
for each area in both cases (baseline and improved) is as follows:
Table 34: Assumed lighting loads for the base case and improved case
Internal Lighting
[LPD W/m²]
Back of house
Kitchen
Breakfast only area
Laundry
Health spa
Linen and store
Base Case
Improved Case
10
12.9
14.0
6.5
9.7
6.5
6.5
8.0
8.7
4.0
6.0
4.0
Compliance Guidance
Design Stage
At the design stage one or all of the following must be
used to demonstrate compliance:


Lighting schedule listing type and number of
bulbs specified.
Electrical layout drawings showing the location
and type of all installed bulbs.
Post-Construction Stage
At the post-construction stage one or all of the
following must be used to demonstrate compliance:



International Finance Corporation
Photographs of the lighting installation. It is not
necessary to take photos of every single
installed lamp, but the auditor must be
convinced that a reasonable proportion has been
checked and verified.
As-built electrical drawings with the lighting
layout if changed from design.
Purchase receipts and delivery notes for lamps
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ENERGY EFFICIENCY MEASURES
HTE27 – LIGHTING CONTROLS FOR CORRIDORS
Requirement Summary
All lighting in shared corridors, common areas, staircases, and outdoor areas must be controlled by
photoelectric switching or dimming, occupancy sensors, or timer controls.
Intention
By installing automatic controls in public, shared, and outdoor spaces, the possibility of lights being left on when
not required is reduced and less energy is consumed.
Approach/Methodologies
There are no calculations involved in the assessment of this measure. In order to claim that it has been
achieved, all lighting in corridors, common areas, staircases, and outdoor areas must have automated controls.
Relevant types of controls include photoelectric switching or dimming, occupancy sensors, or timer controls. The
lighting control shall not be connected to safety or emergency lighting systems.
Potential Technologies/Strategies
Controlling the level of lighting, which means to only light the areas that are in use/occupied or truly need of
light in the hotel. It does not only reduce energy consumption due to artificial lighting, but also can be used to
ambience the lighting to suit different occasions throughout the day. Lighting control devices can range from the
basic 'manual switch' to automatic computer control integrated to a Building Energy Management System
(BEMS), which does not require user operation. The following table describes few types of automatic devices
available in the market:
Table 35: Types of controls for lighting
Type
Timer Controls
Description
They switches lights on and off at pre-set times. There are two types of timer controls:


Occupancy or
Presence Detectors
Time delay switch is most appropriate in spaces where lighting is only used for short
periods of time, such as bathrooms in common areas or corridors (other than the main
thoroughfare). Time delay switches are manually switched on and then automatically switch
off after a set time, which can be adjusted. Time delay or time lag switches can either be
mechanical (pneumatic time delay) where the lighting requirement is less than 30 minutes,
or they can be electronic, which can be programmed to provide a longer delay.
Time controls should always be fitted with a manual override so that out of hours use is still
possible if required. Time controls can either be used to switch lights off when the lighting
is unlikely to be required (such as security lighting during daylight hours), or to switch
lights on at a set time.
Occupancy or presence detectors can be used to switch lights on when movement or presence is
detected and switch them off again when no movement or presence is detected. May be used in areas
of infrequent use by staff and public, such as sections of the hotel that are not much used during
times of low occupancy. Some technologies as follows:



Passive Infrared Sensors (PIR) are the most commonly used occupancy detectors. They
send out infrared beams to detect temperature differences. As PIRs rely on differences in
temperature, they do not always work well in very hot climates, as the background
temperature is similar to human body temperature.
High frequency ultrasound, which responds to any movement.
Microphonics, which can learn to ignore background noise such as air conditioners and do
not rely on line of sight.
As each type of presence-detecting technology has different limitations, many controls use a
combination of the three technologies.
Light Sensors or
Photocell control
Light sensors can be used to switch lights on or off, or in conjunction with dimmers to compensate for
reduced daylight levels in order to maintain a configurable level of light. This system can be used in
corridors or rooms with natural light from windows or skylights.
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ENERGY EFFICIENCY MEASURES
Relationship to Other Measures
Lighting controls can reduce the amount of energy used by lighting, therefore the more efficient the light bulbs
are the less impact the automated controls will have. However, when using controls with energy efficient
lighting, one should make sure to choose the correct light bulbs, which are not influenced by the extensive
switching.
As the controls help to reduce unnecessary use of lighting, cooling loads are reduced. So, both 'Lighting' and
'Cooling Energy' are reduced in the energy graph, while 'Heating Energy' is increased.
Assumptions
The base case assumption is that manual controls will be used for the control of all lighting in corridors and
outdoor spaces. The improved case assumes that these spaces will have automated controls to reduce lighting
usage by 50%.
Compliance Guidance
Design Stage
At the design stage one of the following must be used
to demonstrate compliance:


Electrical layout drawings showing the location of
the occupancy sensors highlighting the sensors
location.
Specification of the sensors/controls from
manufacturer.
Post-Construction Stage
At the post-construction stage one of the following
must be used to demonstrate compliance:



International Finance Corporation
Photographs of lighting controls. It is not necessary
to take photos of every single sensor, but the
auditor must be convinced that a reasonable
proportion has been checked and verified.
As-built electrical layout drawings showing type
and location of sensors/controls if changed from
design.
Purchase receipts and delivery notes for
sensors/controls.
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ENERGY EFFICIENCY MEASURES
HTE28 – OCCUPANCY SENSORS IN BATHROOMS
Requirement Summary
All lighting in bathrooms must be controlled by occupancy sensors.
Intention
By installing occupancy sensors controls in bathrooms, the possibility of lights being left on when not required is
reduced and less energy is consumed.
Approach/Methodologies
There are no calculations involved in the assessment of this measure. In order to claim that it has been
achieved, all lighting in bathrooms must have occupancy sensors controls.
Potential Technologies/Strategies
Controlling the level of lighting, which means to only light the areas, that are occupied or truly need of light, in
the hotel. This reduces energy consumption due to artificial lighting. The World Tourism Organization 30affirm
that the hotel guest bathrooms offer one of the largest energy saving opportunities, as unnecessary extended
operation of the lighting is eliminated. The following are the controls that can be used in the bathrooms of the
hotel:
Table 36: Types of occupancy controls for bathrooms
Type
Occupancy or
Presence Detectors
Description
Occupancy or presence detectors can be used to switch lights on when movement or presence is
detected and switch them off again when no movement or presence is detected. May be used in areas
of infrequent use by staff and public, such as bathrooms. Some technologies as follows:



Passive Infrared Sensors (PIR) are the most commonly used occupancy detectors. They
send out infrared beams to detect temperature differences. As PIRs rely on differences in
temperature, they do not always work well in very hot climates, as the background
temperature is similar to human body temperature.
High frequency ultrasound, which responds to any movement.
Microphonics, which can learn to ignore background noise such as air conditioners and do
not rely on line of sight.
As each type of presence-detecting technology has different limitations, many controls use a
combination of the three technologies.
Automatic control
with key card
Turns off all electrical appliances in guest rooms including the bathroom area (except the minibar)
when the guest rooms are unoccupied
Relationship to Other Measures
Occupancy sensors controls can reduce the amount of energy used by lighting in bathrooms, therefore the more
efficient the light bulbs are the less impact the automated controls will have. However, when using controls with
energy efficient lighting, one should make sure to choose the correct light bulbs, which are not influenced by
the extensive switching. As the occupancy sensors help to reduce unnecessary use of lighting, cooling loads are
reduced. So, both 'Lighting' and 'Cooling Energy' are reduced in the energy graph, while 'Heating Energy' is
increased.
Assumptions
The base case assumption is that manual controls will be used for the control of all lighting in bathrooms. The
improved case assumes that these spaces will have occupancy sensors to reduce lighting usage by 25%.
30
World Tourism Organization (UNTWO). Hotel Energy Solutions (2011), Key Energy Efficiency Technologies Database for SME
Hotels, Hotel Energy Solutions project publications
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ENERGY EFFICIENCY MEASURES
Compliance Guidance
Design Stage
At the design stage one of the following must be used
to demonstrate compliance:


Electrical layout drawings showing the location of
the occupancy sensors highlighting the sensors
location.
Specification of the sensors from manufacturer.
Post-Construction Stage
At the post-construction stage one of the following
must be used to demonstrate compliance:



International Finance Corporation
Photographs of occupancy sensor controls in
bathrooms. It is not necessary to take photos of
every single sensor, but the auditor must be
convinced that a reasonable proportion has been
checked and verified.
As-built electrical layout drawings showing the
location of the occupancy sensors if changed from
design.
Purchase receipts and delivery notes for sensors.
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ENERGY EFFICIENCY MEASURES
HTE29 – SOLAR HOT WATER COLLECTORS
Requirement Summary
This measure can be claimed where solar thermal water heating is specified.
Intention
The installation of solar water heating will reduce the grid electricity (fossil fuels) used by the building for water
heating.
Approach/Methodologies
In order to recognize the energy reductions from installing solar collectors, a user must enter the proportion of
hot water demand that they will deliver. EDGE uses this percentage to offset the amount of energy needed,
displaying an approximate minimum area of collectors required to deliver the proportion of hot water demand.
This will help auditors to check the size of the solar system against the EDGE estimate.
The amount of hot water delivered by the solar collectors is dependent on the amount of solar energy available,
any overshadowing, the orientation and angle of the solar collectors, and the type of solar collectors. The size of
the storage tank also impacts the amount of hot water delivered, as too small of a tank will reduce the quantity
that can be stored. This should be considered by the design team.
Solar collector sizing calculators are available from manufacturers of solar collectors. Alternatively, online
calculators or software can be used.
Potential Technologies/Strategies
There are two types of solar thermal collectors: flat plate and evacuated tube. The area of the collector required
to deliver the stated proportion of hot water demand assumes that flat plate collectors are used, and also
assumes that the collectors are installed at an optimum angle.
Solar collectors should ideally be installed at an angle which is approximately equal to the building location’s
latitude. The collectors should be angled towards the equator (towards the south in the northern hemisphere,
and towards the north in the southern hemisphere). If this is not possible then facing the panels towards the
southeast, southwest, or even west is also acceptable, but panels should not be installed to face north in the
northern hemisphere, and towards the south or east in the southern hemisphere. Solar collectors can also be
installed horizontally, although the efficiency is adversely affected or for optimal efficiency on equatorial
locations.
Table 37: Types of occupancy controls for bathrooms
Type
Description
Flat Plate Collectors
As their name suggests, they are flat and typically black. They are the most commonly used collectors
and are the cheapest option. Flat plate collectors consist of a transparent cover which protects the
absorber plate and reduces heat loss; an absorber plate, which is usually black chrome; tubes
containing a fluid to take heat from the absorber plate; and an insulated backing.
Evacuated Tube
Collectors
Evacuated tubes consist of a row of glass tubes. These glass tubes each contain an absorber plate
fused to a heat pipe containing heat transfer fluid.
Relationship to Other Measures
This measure is inextricably linked to hot water consumption, which EDGE estimates based on the number of
occupants (guests and staff), the efficiency of the hot water boiler, and the flow rates of the showers, laundry
and hand basin faucets. The required area of solar thermal collectors can therefore be reduced significantly by
specifying low-water-use showers and faucets, as well as any water heating recovery technology.
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ENERGY EFFICIENCY MEASURES
Assumptions
The base case assumes that no solar thermal collectors are installed. The improved case reflects 50% of total
hot water demand being met by the solar thermal installation, but the percentage can be adjusted by the user.
Compliance Guidance
In order to demonstrate compliance the design team must briefly describe the system including the type of
solar collector; the capacity of the storage tank and its location; and the size, orientation, and installed angle of
the panels.
EDGE will display the approximate area of panels required to deliver the proportion of hot water claimed by the
design team. The required area is calculated using local climate data and assumes an optimum angle for the
solar panel installation. The calculations assume use of flat plate collectors, therefore if the design team is using
evacuated tube collectors the area can be reduced.
Design Stage
At the design stage the following must be used to
demonstrate compliance:




Manufacturer’s data sheet for the panels specified.
Roof plan and drawings showing location,
orientation, and angle of the panels.
Hotel's hot water system schematic including solar
panels.
Drawings showing that the total area of solar
panels specified is at least as much as the area
estimated by EDGE.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:




As-built plumbing schematics.
As-built roof plan showing the location, orientation,
and angle of the panels.
Purchase receipts and delivery notes for the solar
panels.
Photographs of the installed panels.
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ENERGY EFFICIENCY MEASURES
HTE30 – SOLAR PHOTOVOLTAICS
Requirement Summary
This measure can be claimed if solar photovoltaic panels are installed on the building or the site as long as
energy is used for operation of building. Since the specific proportion of electricity is replaced by renewable
energy, the PV panels are considered an energy efficiency measure.
Intention
Installing solar photovoltaic panels reduces the amount of electricity required from the grid.
Approach/Methodologies
In order to claim this measure, the design team needs to indicate the proportion of electricity demand that they
would like to offset with the PV installation. EDGE will indicate the peak power output kWp required to deliver
that percentage. The design team must be able to demonstrate that the installation is capable of delivering that
kWp. The solar panels’ expected output is measured in kilowatt peak (kWp) and is the theoretical peak output
of the panels under test conditions (Wp). The Wp can be obtained directly from the manufacturer.
Potential Technologies/Strategies
There are many different types of solar photovoltaic systems available and different technologies convert solar
energy into electricity with varying levels of efficiency. Efficiency levels of up to around 20% can be achieved by
some commercially available systems, but others are only capable of delivering as little as 5% efficiency. Design
teams should therefore ensure that the specified system achieves the maximum efficiency possible for the
available capital.
Relationship to Other Measures
In order to maximize the percentage contribution from the solar photovoltaic installation, the electricity demand
should first be minimized by reducing energy consumption (e.g. by using natural instead of mechanical
ventilation or by using automatic lighting controls).
Assumptions
The base case assumes that no photovoltaics are specified. The improved case reflects 25% of total energy
demand being met by the solar panels, but the percentage can be adjusted by the user.
Compliance Guidance
In order to demonstrate compliance, the design team must briefly describe the system, including information on
the type of solar photovoltaic system and the location, size, orientation, and installed angle of the panels. EDGE
will display the approximate kWp that is required to deliver the proportion of electricity demand claimed by the
design team.
Design Stage
At the design stage one or all of the following must be
used to demonstrate compliance:



Manufacturer’s data sheet for the panels specified
with information on Wp per square meter.
Supporting calculation showing the proposed solar
photovoltaics will deliver sufficient electricity to
achieve the claimed proportion of total demand, and
at least as much as the area estimated by EDGE. If
not clear justification should be provided.
The roof plan and/or other drawings showing the
location, orientation, and angle of the panels.
International Finance Corporation
Post-Construction Stage
At the post-construction stage one or all of the
following must be used to demonstrate compliance:



As-built roof plan showing the location,
orientation, and angle of the panels if changed
from design.
Purchase receipts and delivery notes for the solar
panels.
Photographs of the installed panels
82
WATER EFFICIENCY MEASURES
WATER EFFICIENCY MEASURES
Water efficiency is one of the three main resource categories that comprise the EDGE standard. In order to
comply for certification purposes, the design and construction team must review the requirements for selected
measures as indicated and provide the information.
The following pages explain each water efficiency measure by relaying the intention, approach, assumptions,
and compliance guidance requirements.
Figure 6. Screen shot of water saving measures for hotels in EDGE
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83
WATER EFFICIENCY MEASURES
HTW01 – LOW-FLOW SHOWERHEADS IN GUEST ROOMS
Requirement Summary
This measure can be claimed if all showerheads have a flow rate of less than the base case. The base case
assumes a flow rate of 10 liters per minute.
Intention
By specifying low-flow showerheads, water use is reduced without adversely affecting the functionality.
Approach/Methodologies
The flow rate of a shower can be as low as 6 liters per minute or greater than 20 liters per minute. As the flow
rate of a showerhead is dependent on the water pressure, manufacturers often provide a chart which plots the
flow rate at different pressures. In order to improve consistency, the flow rate used for the EDGE assessment
must be that quoted for the operating pressure of 3 bar (43.5 psi).
This measure can be claimed as long as the actual flow rate is entered and is lower than the Base Case. A flow
rate of less than the default value for design contributes to even greater water savings.
Potential Technologies/Strategies
There are many different showerheads available that meet the flow rate required. In order to maintain user
satisfaction at the lower flow rates, some manufacturers mix water with air to cause turbulence in the flow; this
in turn gives an increased sense of pressure without increasing the flow rate.
Relationship to Other Measures
Higher flow rate showers use a significant quantity of hot water. Reducing the flow rate of the shower reduces
the energy required to produce hot water. So, both water consumption due to guest showers, and energy
consumption due to hot water are reduced.
Assumptions
The base case assumption is a flow rate of 10 liters per minute and the improved case is a flow rate of 8 liters
per minute at 3 bar (43.5 psi).
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Plumbing drawings/specifications including make,
model, and flow rate of the showerhead(s).
Manufacturer’s data sheet for the showerhead(s)
confirming the flow rate at 3 bar.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



International Finance Corporation
On site test results by the auditor of the flow rate
at the highest flow per minute, using a timer and a
measurement container. It is also recommended to
use a pressure gauge to measure the water
pressure.
Photographs of the installed showerhead(s).
Purchase receipts and delivery note for the
showerhead(s).
84
WATER EFFICIENCY MEASURES
HTW02 – LOW-FLOW FAUCETS IN GUEST ROOMS
Requirement Summary
This measure can be claimed if the flow rate of the faucets specified for the washbasins in all guest rooms are
less than the base case of 6 liters per minute.
Intention
By specifying low-flow faucets for washbasins, water use is reduced without adversely affecting the
functionality.
Approach/Methodologies
As the flow rate of a faucet is dependent on the water pressure, manufacturers often provide a chart that plots
the flow rate at different pressures. In order to improve consistency, the flow rate used for the EDGE
assessment must be that quoted for the operating pressure of 3 bar (43.5 psi).
If the measure is claimed, then the assumed flow rate is 2 liters per minute. If the flow rate is greater than 2
liters per minute but lower than the base case of 6 liters per minute, the measure can still be claimed as long as
the actual flow rate is entered. The lowest the flow rate the greater the water savings.
Potential Technologies/Strategies
There are many different faucets available that meet the flow rate required. In order to maintain user
satisfaction at the lower flow rates, some manufacturers mix water with air to cause turbulence in the flow; this
in turn gives an increased sense of pressure without increasing the flow rate. Spray faucets are another
alternative that can be considered for washbasins.
Flow restrictors or aerators can be used to reduce the flow rate of the faucets specified, which may be a cheaper
alternative to purchasing a low-flow faucet.
Relationship to Other Measures
Reducing the flow rate of the washbasin faucets reduces the hot water demand and the energy required to
produce hot water.
Assumptions
The base case assumption is a flow rate of 6 liters per minute to all faucets of the guest rooms and the
improved case is a flow rate of 2 liters per minute.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Plumbing drawings/specifications including make,
model, and flow rate of the washbasin faucet(s) or
flow restrictor(s).
Manufacturer’s data sheet for faucet(s)/flow
restrictor(s) confirming the flow rate at 3 bar.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



International Finance Corporation
On site test results by the auditor of the flow rate
at the highest flow per minute, using a timer and a
measurement container. It is also recommended to
use a pressure gauge to measure the water
pressure.
Photographs of the installed faucet(s) or flow
restrictor(s).
Purchase receipts and delivery note for faucet(s) or
flow restrictor(s).
85
WATER EFFICIENCY MEASURES
HTW03 – DUAL FLUSH FOR WATER CLOSETS IN GUEST ROOMS
Requirement Summary
This measure can be claimed when water closets have a dual flush in all the bathrooms of the guest rooms.
Intention
Fitting dual flush water closets helps to reduce the water used for flushing by providing a reduced flush option
when a full flush is not required.
Approach/Methodologies
The measure can be claimed if the main flush is less than the base case of 8 liters and/or if the second flush is
less than the base case of 6 liters as long as the default flush volumes for the improved case are replaced with
the actual values provided by the manufacturer. If the flush volume is lower than 6 liters for the first flush
and/or 3 liters for the second flush then the default value should be replaced with the actual values in order to
recognize the even greater performance.
Potential Technologies/Strategies
In some cases dual-flush water closets can increase the volume of water used if the use is not clear. For this
reason the design team should be careful to select dual-flush water closets with clear intuitive controls. The
Environmental Protection Agency in the US has set up a label31 which has tests for water efficiency and
performance. The EPA website is a useful reference to identify dual flush toilets which have equivalent
performance to toilets with higher flush volumes.
Relationship to Other Measures
The contribution that the measure makes to the overall performance is not affected by any other measure.
However, when this measure is selected the energy consumption is impacted due to water pumps (this portion
of the energy consumption is included within “Others”).
Assumptions
The base case assumption is a flush volume of 8 liters. The improved case assumes a flush volume of 6 liters for
the main flush and 3 liters for the reduced flush.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:


31
Plumbing drawings/specifications including make,
model, and flush volumes of water closet(s).
Manufacturer’s data sheet for water closet(s) with
information on the flush volume of the main and
reduced flushes.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


Photographs of installed water closet(s).
Purchase receipts and delivery note for water
closet(s).
http://www.epa.gov/WaterSense/index.html
International Finance Corporation
86
WATER EFFICIENCY MEASURES
HTW04 – WATER-EFFICIENT FRONT LOADING WASHING MACHINE
Requirement Summary
This measure can be claimed when all the washing machines used in the laundry of the hotel are high efficient
front loading.
Intention
Using high efficient front loading washing machines reduces the water used for laundry. Other benefits, of high
efficient washing machines, include energy saving due to the reduction of hot water use, better performance in
cleaning the clothes, reduce fabric wear, and usually less detergent use.
Approach/Methodologies
The measure can be claimed if all the washing machines in the laundry use 6 liters of water per kilogram of
clothes washed or less.
Potential Technologies/Strategies
There are two types of washing machines available in the market, top loading and front loading. While top
loading need more water in order to cover the clothes inside, the front loading require about a third. The high
efficiency washers are high-tech machines that use less water (both hot and cold water) and energy, while are
more effective in cleaning the clothes compared to the standard ones. This is because in the front loading the
washer moves the clothes through the water using gravity to create more agitation.
Relationship to Other Measures
Using a water-efficient washing machine not only reduces cold water demand but also hot water demand.
Therefore, when this measure is selected the energy consumption is decreased due to water heating, as well as
miscellaneous equipment, which is included within "Others".
Assumptions
The base case assumption is a standard washing machine that uses 10 liters per kilogram of clothes per cycle,
while the improved case assumes a water usage of 6 liters per kilogram of clothes per cycle. This is equivalent
to Water Consumption Factor (WCF)* of 5.94l/kg/cycle or 4.5gal/cuft/cycle.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:

Manufacturer’s data sheet for washing machine(s)
selected with information on the water consumption
and maximum load capacity in kilograms.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


Photographs of installed front loading washing
machine(s).
Purchase receipts and delivery note for washing
machine(s).
87
WATER EFFICIENCY MEASURES
HTW05 – WATER-EFFICIENT URINALS IN ALL OTHER BATHROOMS
Requirement Summary
This measure can be claimed when urinals in all bathrooms except the ones guest rooms have a flush volume
which is lower than the base case. The base case flush volume is 4 liters.
Intention
Fitting low-flush urinals reduces the water used for flushing, ensuring efficient water use and high level of user
satisfaction with flushing performance.
Approach/Methodologies
The measure can be claimed if the flush volume is lower than the base case of 4 liters, as long as the default
flush volumes for the improved case are replaced with the actual values provided by the manufacturer. If the
flush volume is lower than 2 liters then the default value should be replaced with the actual values in order to
recognize the even greater performance. This is because in the market are urinals available that do not use any
water. For this measure the manufacturer should specify a maximum flush volume of the urinal fixture. For
waterless urinals a value of 0.001Lt/flush should be entered to the box provided.
Potential Technologies/Strategies
Urinals are only provided in male bathrooms and only accept liquid waste. Their water saving potential depends
of the number of male users in the hotel, EDGE assumes in average use urinals 2 out of 3 times of bathroom
use.
Urinals that are designed to be non-adjustable above their flush volume and that are provided with drain trap
functionality tend to save more water. Pressurize flushing devices and a valve provide controls and therefore
water savings.
In some cases water efficient urinals can result in an increased risk of blockages caused by the reduced volume
of water. The Environmental Protection Agency in the US has set up a label, WaterSense' which has tests for
water efficiency and performance32. The WaterSense label helps purchasers easily identify high–performing,
water–efficient urinals, which can be found in EPA website, as a reference to identify water efficient urinals.
Type of urinal
Description
High efficiency
Urinals that flushes 2 liters or less, which are currently available in the market from
several manufactures.
Waterless or nonwater
These urinals eliminate completely the flush valves and water use. They need special
maintenance to control odors and blockages with "urine stone" deposits in the drains.
This adds operation costs, as well as reducing life expectancy which should be taken
into account.
Wall-mounted urinals
with flush valves
These urinals are flushed after each use, either manually or automatically. The
automatic controls can be a timer or a valve, which are useful in bathrooms of high
use, such as conference areas.
Relationship to Other Measures
The contribution that the measure makes to the overall performance is not affected by any other measure.
However, when this measure is selected the energy consumption is slightly impacted due to water pumps (this
portion of the energy consumption is included within “Others”).
32
http://www.epa.gov/WaterSense/index.html or http://www.epa.gov/WaterSense/products/urinals.html
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88
WATER EFFICIENCY MEASURES
Assumptions
The base case assumption is a flush volume of 4 liters. The improved case assumes a flush volume of 2 liters.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Plumbing drawings/specifications including make,
model, and flush volume of the urinal(s).
Manufacturer’s data sheet for urinal(s) with
information on the flush volume.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


Photographs of installed urinal(s).
Purchase receipts and delivery note for urinal(s).
89
WATER EFFICIENCY MEASURES
HTW06 – DUAL FLUSH FOR WATER CLOSETS IN ALL OTHER BATHROOMS
Requirement Summary
This measure can be claimed when water closets have a dual flush in all other bathrooms not including guest
rooms.
Intention
Fitting dual flush water closets helps to reduce the water used for flushing by providing a reduced flush option
when a full flush is not required.
Approach/Methodologies
The measure can be claimed if the main flush is less than the base case of 8 liters and/or if the second flush is
less than the base case of 6 liters as long as the default flush volumes for the improved case are replaced with
the actual values provided by the manufacturer. If the flush volume is lower than 6 liters for the first flush
and/or 3 liters for the second flush then the default value should be replaced with the actual values in order to
recognize the even greater performance.
Potential Technologies/Strategies
In some cases dual-flush water closets can increase the volume of water used if the use is not clear. For this
reason the design team should be careful to select dual-flush water closets with clear intuitive controls. The
Environmental Protection Agency in the US has set up a label33 which has tests for water efficiency and
performance. The EPA website is a useful reference to identify dual flush toilets which have equivalent
performance to toilets with higher flush volumes.
Relationship to Other Measures
The contribution that the measure makes to the overall performance is not affected by any other measure.
However, when this measure is selected the energy consumption is impacted due to water pumps (this portion
of the energy consumption is included within “Others”).
Assumptions
The base case assumption is a flush volume of 8 liters. The improved case assumes a flush volume of 6 liters for
the main flush and 3 liters for the reduced flush.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:


33
Plumbing drawings/specifications including make,
model, and flush volumes of water closet(s).
Manufacturer’s data sheet for water closet(s) with
information on the flush volume of the main and
reduced flushes.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


Photographs of installed water closet(s).
Purchase receipts and delivery note for water
closet(s).
http://www.epa.gov/WaterSense/index.html
International Finance Corporation
90
WATER EFFICIENCY MEASURES
HTW07 – AERATORS & AUTO SHUT-OFF FAUCETS IN ALL OTHER
BATHROOMS
Requirement Summary
This measure can be claimed if the flow rate of the faucets specified for the washbasins in all the bathrooms
except the guest rooms bathrooms are less than the base case of 6 liters per minute. This low flow rate should
be obtained through the use of aerators and auto shut off controls.
Intention
By specifying aerators and auto shut off faucets for washbasins, water use is reduced without adversely
affecting the functionality.
Approach/Methodologies
As the flow rate of a faucet is dependent on the water pressure, manufacturers often provide a chart that plots
the flow rate at different pressures. In order to improve consistency, the flow rate used for the EDGE
assessment must be that quoted for the operating pressure of 3 bar (43.5 psi).
If the measure is claimed, then the assumed flow rate is 2 liters per minute. If the flow rate is greater than 2
liters per minute but lower than the base case of 6 liters per minute, the measure can still be claimed as long as
the actual flow rate is entered. The lowest the flow rate the greater the water savings.
Potential Technologies/Strategies
This measure includes two technologies fitted to the faucet, the aerators and the auto shut-off, which should be
purchase as one product.
The aerators are small water saving devices attached to the faucet that maintain user satisfaction at the lower
flow rates. They mix water with air to cause turbulence in the flow; this in turn gives an increased sense of
pressure without increasing the flow rate. They are also called flow regulators.
The auto shut-off faucets are activated by a push action or electronic sensors that allow the water flow and
last for a programmed time, usually 15 seconds. After this period of time the faucet shuts-off automatically,
which is ideal for public and unsupervised washing areas.
Relationship to Other Measures
Reducing the flow rate of the washbasin faucets of all the other bathrooms of the hotel reduces the hot water
demand and the energy required to produce hot water.
Assumptions
The base case assumption is a flow rate of 6 liters per minute to the faucets of all other spaces except the guest
rooms, these faucets do not have an auto shut-off technology. The improved case has an auto shut-off faucet
with a flow rate of 2 liters per minute in all the bathrooms except for the guest rooms’ bathrooms.
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91
WATER EFFICIENCY MEASURES
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Plumbing drawings/specifications including make,
model, auto shut-off mechanism and flow rate of
the washbasin faucet(s)
Manufacturer’s data sheet for faucet(s)/flow
aerator(s) confirming the flow rate at 3 bar.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



International Finance Corporation
On site test results by the auditor of the flow rate
at the highest flow per minute, using a timer and a
measurement container. It is also recommended to
use a pressure gauge to measure the water
pressure.
Photographs of the installed faucet(s).
Purchase receipts and delivery note for faucet(s)
which includes make, model and auto shut-off
mechanism.
92
WATER EFFICIENCY MEASURES
HTW08 – WATER- EFFICIENT DISHWASHERS
Requirement Summary
This measure can be claimed if all the dishwashers installed in the hotel are water efficient (low consumption).
This can be demonstrated when the purchased dishwasher(s) use less water than the base case. The base case
dishwasher uses 8.9 liters per rack.
Intention
Minimize the water consumed by the dishwashers installed in the hotel.
Approach/Methodologies
The dishwasher consumption can be as low as 7 liters per load or greater than 21 liters per load. In a load two
racks can be filled up. EDGE measures the water consumption per rack, which is calculated with the maximum
total water consumption in liters divided by the number of racks in the dishwasher. The maximum total water
consumption is taken from the manufactures datasheet on the cycle of the dishwasher that uses the most
water. This measure can be claimed as long as the dishwasher uses 5.3 liters per rack or less.
Potential Technologies/Strategies
Dish washers overview
About 60% of the energy used
by a dishwasher goes towards
water heating; therefore
models that use less water
also use less energy.
Key features for Efficiency
An efficient dishwasher should:








Be the right size for the hotel.
Go for full load.
Have several wash cycles.
Skip pre-rinse
Have soil sensors, which test how dirty dishes are and adjust the cycle to reduce
water and energy use.
Have more efficient jets, which use less energy to spray detergent and water.
Have ‘no-heat’ drying feature, which circulates room air through the dishwasher by
fans, rather than using an electric heating.
Have improved water filtration
In terms of dishwashers, the way that occupant use them also influence the water performance. It is important
to provide users with guidelines outlining the benefits of these appliances, and the best way to achieve
maximum efficiency.
Relationship to Other Measures
Water reduction in the 'Kitchen' section of the water chart is expected by water efficient dishwashers. Moreover,
it shows reductions in energy due to equipment and pumps which is part of 'Others'.
Assumptions
The base case assumes standard dishwashers with a water consumption of 8.9 liters per rack, while the
improved case assumes 5.3 liters per rack, which is 40% more efficient.
Compliance Guidance
Design Stage
At the design stage the one of the following must be
used to demonstrate compliance:


Summary list of the dishwasher(s) to be installed
in the building, including quantity and proof of
maximum water use.
Specifications from manufacture detailing water
use.
Post-Construction Stage
At the post-construction stage one of the following
must be used to demonstrate compliance:



International Finance Corporation
Updated summary list of dishwasher(s) installed in
the building including quantity, manufacturer and
model;
Proof of maximum water consumption from
manufacture.
Purchase receipts and delivery note for dishwashers
93
WATER EFFICIENCY MEASURES
HTW09 – PRE-RINSE VALVE FOR RINSING OPERATION
Requirement Summary
This measure can be claimed if the kitchens are fitted with low flow pre-rinse valves for rinsing the dishes prior
to be placed in the washing machine. The pre-rinse valve specified should be 2.1 liters per minute or less.
Intention
By specifying low-flow pre-rinse valve, water use is reduced compared to a manually rinse of the dishes.
Approach/Methodologies
As the flow rate of the pre rinse valve is dependent on the water pressure, manufacturers often provide a chart
that plots the flow rate at different pressures. In order to improve consistency, the flow rate used for the EDGE
assessment must be that quoted for the operating pressure of 3 bar (43.5 psi).
If the measure is claimed, then the assumed flow rate is 2.1 liters per minute or less.
Some of the benefits of having an efficient pre rinse valve in the kitchen of the hotel include having an efficient
cleaning but using less water and energy, which then reduce the operational costs.
Potential Technologies/Strategies
There are many different pre-rinse valves available in the market, however as the flow rate required is low,
efficient spray valves need to meet 2.1 liters per minute flow rate. In order to maintain user satisfaction at the
lower flow rates, manufacturers mix water with air to cause turbulence in the flow; this in turn gives an
increased sense of pressure without increasing the flow rate. Pre-rinse spray valves require a lot of pressure,
which is given by the air within the valve, to remove the food waste prior to dishwashing. The savings are even
more noticeable because pre-rinse valves use hot water, so when water is reduced the use of energy is also
dropped.
Relationship to Other Measures
Water reduction in the 'Kitchen' section of the water chart is expected by low flow pre-rinse valves. Moreover, it
shows reductions in energy due to 'water heating' and water pumps which is part of 'Others'.
Assumptions
The base case assumption is a flow rate of 5.2 liters per minute and the improved case is a flow rate of 2.1
liters per minute.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Plumbing drawings/specifications including make,
model, and flow rate of the pre-rinse valve(s).
Manufacturer’s data sheet for pre-rinse valve(s)
confirming the flow rate at 3 bar.
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



International Finance Corporation
On site test results by the auditor of the flow rate
at the highest flow per minute, using a timer and a
measurement container. It is also recommended to
use a pressure gauge to measure the water
pressure.
Photographs of the installed pre-rinse valve(s).
Purchase receipts and delivery note for pre-rinse
valve(s).
94
WATER EFFICIENCY MEASURES
HTW10 – WATER EFFICIENT KITCHEN FAUCETS
Requirement Summary
This measure can be claimed if the flow rate of the faucets specified for the kitchen sinks is less than the base
case of 15.9 liters per minute.
Intention
By specifying low-flow faucets for kitchen sinks, water use is reduced without adversely affecting the
functionality.
Approach/Methodologies
As the flow rate of a faucet is dependent on the water pressure, manufacturers often provide a chart that plots
the flow rate at different pressures. In order to improve consistency, the flow rate used for the EDGE
assessment must be that quoted for the operating pressure of 3 bar (43.5 psi).
If the measure is claimed, then the assumed flow rate is 12.7 liters per minute. If the flow rate is greater than
12.7 liters per minute but lower than the base case of 15.9 liters per minute, the measure can still be claimed
as long as the actual flow rate is entered. A flow rate of less than 12.7 liters per minute contributes to even
greater water savings.
Potential Technologies/Strategies
There are many different faucets available that meet the flow rate required. In order to maintain user
satisfaction at the lower flow rates, some manufacturers mix water with air to cause turbulence in the flow; this
in turn gives an increased sense of pressure without increasing the flow rate.
Flow restrictors or aerators can be used to reduce the flow rate of the faucets specified, which may be a cheaper
alternative to purchasing a low-flow faucet.
Relationship to Other Measures
Higher flow rate kitchen faucets use a significant quantity of hot water. Reducing the flow rate of the kitchen
faucets reduces the energy required to produce hot water.
Assumptions
The base case assumption is a flow rate of 15.9 liters per minute and the improved case is a flow rate of 12.7
liters per minute at 3 bar.
Compliance Guidance
Design Stage
At the design stage one of the following must be used
to demonstrate compliance:


Plumbing drawings/specifications including make,
model, and flow rate of kitchen(s) faucet(s) or flow
restrictor(s).
Manufacturer’s data sheet for faucet(s)/flow
restrictor(s) confirming the flow rate at 3 bar.
Post-Construction Stage
At the post-construction stage one of the following
must be used to demonstrate compliance:



International Finance Corporation
On site test results by the auditor of the flow rate
at the highest flow per minute, using a timer and a
measurement container. It is also recommended to
use a pressure gauge to measure the water
pressure.
Photographs of the installed faucet(s) or flow
restrictor(s).
Purchase receipts and delivery note for faucet(s) or
flow restrictor(s).
95
WATER EFFICIENCY MEASURES
HTW11 – WATER EFFICIENT LANDSCAPING
Requirement Summary
This measure can be claimed if water efficient landscaping is incorporated within the hotel. Water efficient
landscaping measure can be claimed if on average less than 4 liters of water (excluding rainwater) per square
meter of landscaping a day being used.
Intention
Water efficient outdoor landscaped areas can reduce the use of fresh water from the municipal supply, as well
fertilizers and usually maintenance cost, but preserving the habitat of plants and wildlife.
Approach/Methodologies
This measure can only be claimed if the outdoor landscaping areas including lawns, gardens and ponds, will use
less than 4 liters of water (excluding rainwater) a day throughout the year. This can be achieved reducing the
areas planted with water intensive plants. Instead more native and adoptive plantation can reduce irrigation
needs. Detailed guidance for selecting water efficient plants according to the local weather conditions would
normally be carried out by the landscape designer or the supplier of the plants. However the following can be
used as a rough guide:
Then, the total outdoor landscaping area, including lawns, gardens and ponds, is calculated
𝑳𝒂𝒏𝒅𝒔𝒄𝒂𝒑𝒆 𝑾𝒂𝒕𝒆𝒓 𝒄𝒐𝒏𝒔𝒖𝒎𝒑𝒕𝒊𝒐𝒏 =
𝑳𝒂𝒏𝒅𝒔𝒄𝒂𝒑𝒆 𝑾𝒂𝒕𝒆𝒓 𝒓𝒆𝒒𝒖𝒊𝒓𝒆𝒎𝒆𝒏𝒕𝒔 − 𝑹𝒂𝒊𝒏𝒇𝒂𝒍𝒍 𝑽𝒐𝒍𝒖𝒎𝒆
𝒕𝒐𝒕𝒂𝒍 𝒐𝒖𝒕𝒅𝒐𝒐𝒓 𝒍𝒂𝒏𝒅𝒔𝒄𝒂𝒑𝒊𝒏𝒈 𝒂𝒓𝒆𝒂
Where: Landscape Water requirements = Amount of water needed per day for all the plants within the outdoor
landscaping area (liters)
Rainfall Volume = daily average annual rainfall (liters)
Total outdoor landscaping area = Area of outdoor lawns, gardens and ponds (m²)
A drip irrigation or under surface system can help reduce the water consumption in landscape as appose to
sprinkler system.
Potential Technologies/Strategies
According to studies 'up to 50 percent of the water applied to lawns and gardens is not absorbed by the plants.
It is lost through evaporation, runoff, or being pushed beyond the root zone because it is applied too quickly or
in excess of the plants’ needs'34. In order to offset this, the following are the main considerations when
designing a water efficient landscaping area:



Use native and low water-using plants, as they require very little water beyond the local rainfall.
Create zones of vegetation according to their water requirements. In this way, less water is wasted in
irrigation as each zone is watered differently.
Use of appropriate irrigation system.
Relationship to Other Measures
Claiming this measure reduces the water demand use for landscaping only.
Assumptions
The base case assumption is that 6 liters of fresh water per square meter a day is used on landscaping areas.
The improved case assumes that 4 liters per square meter a day is use in the landscaping area.
34
US Environmental Protection Agency. http://www.epa.gov/WaterSense/docs/water-efficient_landscaping_508.pdf
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WATER EFFICIENCY MEASURES
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



A landscape plan showing the zoning for plants and
the type of plants use highlighting native species
and the irrigation system selected.
Description of the water requirements use in the
landscape areas
Calculation of the landscape water consumption in
liters/m²/day.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


Photographs of the planted species, landscaping
area and irrigation system.
Purchase receipt and delivery note for the plants
and vegetation.
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WATER EFFICIENCY MEASURES
HTW12 – SWIMMING POOL COVER
Requirement Summary
This measure can be claimed if the hotel has pool(s), including spa pools, and these are fitted with a cover to
prevent water and heat losses through evaporation.
Intention
The use of a cover of the entire pool(s) can reduce the use of fresh water from the municipal supply as well as
energy due to the water and heat losses through evaporation from the surface of the pool.
It can also protect the pool from debris contamination, which reduces the use of chemicals and maintenance. In
hot climates it can provide shadow, but when the pool is heated it prevents from heat losses during the night or
when the pool is not in use.
Approach/Methodologies
This measure can only be claimed if all the pools including outdoor and indoor (spa pools) have a suitable
(resistant and thick material) cover fitted to the entire pool surface. A suitable cover will include the following
characteristics:





Pool treatment chemicals and UV light resistance;
Durable material;
Insulation properties, as well as full fitted;
Easy to store and utilize; and
Safe for both pool users and staff.
Potential Technologies/Strategies
Most pools lose water due to evaporation from the surface and the heat loss of pools occurs at the surface due
mostly to evaporation, but also radiation to the sky. This issue can be easily addressed with an affordable
solution such as the pool cover. Pool covers have the following benefits:
Benefits
Description
Reduce the water
consumption
When the pool is not in use, the surface water is evaporated to the atmosphere. A pool
cover reduces the evaporation rate up to 98%, thus reduce the use of more water to fill
the pool.
Reduce the energy
consumption
In heated pools, the pool cover can be used both at daytime and nighttime saving
energy, as it can gain heat as well as prevent the heat losses. Standard pool
temperature can rise up to 4ºC (especially dry and cold environments), if the sun pass
through a transparent cover and heat the surface of the pool. Then at night, when there
is no heat gain, the cover retains the heat reducing radiant heat losses and the
evaporation rate.
Reduce chemicals
consumption
When the pool is covered, it is protected from debris (leaves, twigs and litter)
contamination and therefore less chemical (chlorine) to clean up the pool is required. In
addition, chemicals are not dispersed to the atmosphere due to the reduction of the
evaporation rate.
Reduce the need of
mechanical
ventilation (halls)
If evaporation is prevented when the pool cover is in place, then less mechanical
ventilation is required in enclosed pool halls. In addition, dehumidifiers can be shut-off
during out of hours. These two factors also reduce the energy consumption due to the
mechanical ventilation system.
Reduce
maintenance
Both building and pool maintenance are reduced. This is because the reduction of
humidity and condensation when the pool cover is on place, lessen the maintenance to
prevent mold on the building structure (especially in pool halls). In addition, the pool
maintenance is also lessen are chemicals are saved and debris contamination is avoided.
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WATER EFFICIENCY MEASURES
The following types of pool covers are available in the market:
Types
Description
Bubble covers also
Transparent bubble or
Bubble Solar
This cover is especially designed for outdoor pools that gain heat from the sun, as it
reduces solar energy absorption by up to 15%, but retains the heat of the pool
while out of hours. It is made of a thick grade plastic, in which two bubbles are
joined together by a waistline center section and ultraviolet (UV) inhibitors.
Vinyl
Vinyl covers are generally opaque and made of a heavier material. It prolongs its
use but do not benefit from solar heat gains.
Insulated Vinyl
Same as the material above, but it is provided with a thin layer of insulation
between the vinyl layers, to reduce the heat loss from the pool.
Relationship to Other Measures
Claiming this measure reduces the water demand for pool and also the energy due to water heating.
Assumptions
The base case assumption is that the pool does not have a fitted cover. The improved case assumes that the
pool cover is adequately fitted and that the pool reduces the evaporation rate, therefore 30% of water is saved
each time that the pool is refilled.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:

Sizing calculations and manufacturer’s data sheet
for a pool cover that fits the whole pool.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


Photographs of the installed pool cover
Purchase receipt and delivery note for the pool
cover.
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WATER EFFICIENCY MEASURES
HTW13 – CONDENSATE WATER RECOVERY
Requirement Summary
This measure can be claimed if condensate water recovery device with capacity to collect all condensate water
from cooling system is installed and the collected condensate water being used in landscaping, toilet flushing or
outdoor uses.
Intention
By recovering the condensate water from HVAC equipment the use of fresh water from the municipal supply can
be reduced.
Approach/Methodologies
Hotels can benefit of the condensate water recovery, as it does not require much treatment and save water for
other purposes within the building and landscaping.
In order to qualify the design team must demonstrate that the HVAC system has a collection device for the
condensate water recovered. The collected condensate must have a piping system and collection tank or can be
directed to rain water collection tank if present. Water collected should be used in the building such as toilet
flushing or on site or irrigation.
Potential Technologies/Strategies
In the context of buildings, condensate water recovery aims to re-use the water arising from the
dehumidification of the air in HVAC or refrigeration systems. There, when the air passes through the cold coil,
the temperature of the air is decreased and the vapor (humidity) changes from gas to liquid, which can then be
removed as condensate. It is essentially distilled water with low mineral content, but it might contain bacteria,
as Legionella35. This water can potentially be used everywhere in the building if proper treatment to address
biological contaminants is considered. Potential use of condensate water includes:







Irrigation: Generally safe to use without treatment, if use as surface irrigation;
Cooling towers: Safe to use without treatment;
Water for decorative ponds or fountains – treatment is needed;
Toilet and urinal flushing– treatment is needed;
Rainwater recycle system: condensate can be a source to feed the system;
Laundry and washing: biocide treatment required; and
Swimming pool: biocide treatment36.
Condensate can be a constant source of water if HVAC system is in use, it can generate between 11 to 40
liters/day per 100m² of conditioned space37, which depend of the HVAC system type and operation.
Collected water must be in accordance with local or international health and sanitary code requirements
(whichever are more stringent).
Relationship to Other Measures
Claiming this measure reduces the water demand for all uses considered by EDGE, from public area
(landscaping, WC and urinals) or laundry to guest WC, showers and faucets.
Assumptions
The base case assumes no condensate water recovery from HVAC, while the improved case assumes that all
condensate water generated from cooling system are recovered.
35
36
37
Boulware, B. Environmental leader magazine. Air Conditioning Condensate Recovery, January 15, 2013.
idem
Alliance for Water Efficiency
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WATER EFFICIENCY MEASURES
Compliance Guidance
In order to demonstrate compliance, the design team must provide documentation to support the claims.
Design Stage
At the design stage the following must be used to
demonstrate compliance:


Calculations for condensate water recovery
specifying cooling load and water collected in
liters per day.
Hydraulic layout drawings showing the location of
the recovery, collection and reuse technology.
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


As-built hydraulic drawings with the location of the
recovery, collection and reuse technology.
Photographs of installed equipment related to the
system.
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WATER EFFICIENCY MEASURES
HTW14 – RAINWATER HARVESTING SYSTEM
Requirement Summary
This measure can be claimed if the rainwater collection system provides the water supply for use within the
building.
Intention
Rain water in a climatic zone with excessive rainfall can reduce the use of fresh water from the municipal
supply.
Approach/Methodologies
This measure can only be claimed if the rainwater collected is used in the building. A rainwater collection used
for landscaping will not satisfy the requirements of the measure. In order to qualify the collected rainwater has
to be used for indoor uses (such as flushing toilets or showers). EDGE automatically calculates the approximate
maximum quantity of water that can be collected by a rainwater harvesting system using rainfall data from the
project location and the size of the roof area as provided on the design sheet.
Detailed guidance for sizing a rainwater collection system is available online and would normally be carried out
by the supplier of the system. However the following can be used as a rough guide:
𝑹𝒂𝒊𝒏𝒘𝒂𝒕𝒆𝒓 𝑯𝒂𝒓𝒗𝒆𝒔𝒕𝒊𝒏𝒈 (𝒎𝟑 ) = (𝑪𝒂𝒕𝒄𝒉𝒎𝒆𝒏𝒕 𝑨𝒓𝒆𝒂 ∗ 𝑹𝒂𝒊𝒏𝒇𝒂𝒍𝒍 𝑽𝒐𝒍𝒖𝒎𝒆 ∗ 𝑹𝒖𝒏 𝒐𝒇𝒇 𝑪𝒐𝒆𝒇𝒇𝒊𝒄𝒊𝒆𝒏𝒕/𝟏𝟎𝟎𝟎)
Where:
Area of catchment = area of rooftop (m²)
Rainfall Volume = average annual rainfall (mm), also called “amount potential”
Run-off Coefficient = varies depending on the roof type, some examples as follows:
Run-off Coefficient: Metal roof - 0.95, Concrete/asphalt roof - 0.90, Gravel roof - 0.80
Potential Technologies/Strategies
The main consideration when designing a rainwater harvesting system is adequate sizing of the storage tank.
The supplier/designer of the system should be able to advise on appropriate sizing, but the two key factors to
consider when sizing the tank are the rate of supply (local rainfall data and collection area) and the demand
(water use per day).
When harvesting the rain water, a dual piping system should be used to separate the rain water from the main.
Collected water must be in accordance with local or international health and sanitary code requirements
(whichever are more stringent).
Relationship to Other Measures
Claiming this measure reduces the water demand for all uses considered by EDGE.
Assumptions
The base case assumption is that no rainwater is harvested. The improved case assumes that the rainwater
harvesting system is adequately sized and that the rainwater collected is used internally for such purposes as
flushing toilets and showers.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:


A system schematic showing the collection area,
feed pipes, and storage tank.
Sizing calculations for the rainwater harvesting
system.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:


Photographs of the installed rainwater harvesting
system and dual piping.
Purchase receipt and delivery note for the rainwater
harvesting/storage system.
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WATER EFFICIENCY MEASURES
HTW15 – GREY WATER TREATMENT AND RECYCLING SYSTEM
Requirement Summary
This measure can be claimed if there is a grey water recycling system that reuses waste water from kitchens,
laundry and bathrooms for the purpose of flushing toilets.
Intention
By recycling the grey water the use of fresh water from the municipal supply can be reduced.
Approach/Methodologies
If this measure is claimed EDGE automatically calculates the potential supply and reduces the water demand for
flushing toilets by that amount. EDGE assumes that all wastewater from kitchens, laundry and bathrooms is
collected and stored in sufficient quantities to meet the demand for flushing toilets. If the quantity of
wastewater is insufficient, then EDGE simply deducts the wastewater available from the total demand.
When recycling the water, a dual piping system should be used to separate the recycled water from the main.
Treated water must be in accordance with local or international health and sanitary code requirements
(whichever is more stringent).
A water balance model could be produced by the design team to understand the potential for water recycling.
Potential Technologies/Strategies
Some jurisdictions may not permit the use of grey water in buildings for flushing; in such cases this measure
cannot be claimed. Use of recycled water for irrigation does not count toward this measure.
Relationship to Other Measures
The quantity of wastewater available depends on the efficiency of water fittings; therefore more efficient
buildings may have insufficient water available to completely offset the demand for flushing.
Assumptions
The base case assumes that there is no grey water recycling. The improved case assumes that all grey water is
re-used in the building for flushing water closets.
Compliance Guidance
Design Stage
At the design stage the following must be used to demonstrate
compliance:



A system schematic showing the plumbing layout including the dual
plumbing lines.
Manufacturer’s data sheet of the specified grey water treatment plant.
Calculations including the following:
o Designed capacity of the grey water treatment system in m3/day.
o Quantity of grey water available daily to recycle in liters/day.
o Efficiency of the grey water system to produce treated water in
liters/day.
o Water balance chart.
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Post-Construction Stage
At the post-construction stage the
following must be used to demonstrate
compliance:



Date stamped photographs of the
installed system.
Purchase receipt and delivery note
for the water treatment and storage
system.
Updated calculations or
specifications if necessary.
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WATER EFFICIENCY MEASURES
HTW16 – BLACK WATER TREATMENT AND RECYCLING
Requirement Summary
This measure can be claimed if there is a black water recycling system that reuses wastewater from all internal
uses.
Intention
To reduce the use of water from the municipal supply and reduction of load on the local water and sewage
infrastructure, a black water recycling system should be used.
Approach/Methodologies
If this measure is claimed EDGE automatically calculates the potential supply and reduces the water demand for
flushing toilets by that amount. EDGE assumes that most of the wastewater from the building is collected,
treated, and stored in sufficient quantities to meet the demand for future flushing.
A water balance model could be produced by the design team to understand the potential for water recycling.
Treated water must be in accordance with local or international health and sanitary code requirements
(whichever more stringent).
Potential Technologies/Strategies
Some jurisdictions may not permit the use of recycled black water in buildings for future flushing; in such cases
this measure cannot be claimed.
When recycling the water, a dual piping system should be used to separate the recycled water from the main.
Relationship to Other Measures
The contribution that the measure makes to the overall performance is not affected by any other measure.
Assumptions
The base case assumes that there is no black water harvesting. The improved case assumes that all black water
is re-used in the building for flushing water closets, and none is diverted for landscaping.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



A system schematic showing the plumbing layout
including the dual plumbing lines.
Manufacturer’s data sheet of the specified black water
treatment plant.
Calculations including the following:
o
o
o
o
Designed capacity of the black water treatment system in
m3/day.
Quantity of black water available daily to recycle in liters/day.
Efficiency of the black water system to produce treated water
in liters/day.
Water balance chart.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following
must be used to demonstrate compliance:



Photographs of the installed system.
Purchase receipt and delivery note for the
water treatment and storage system.
Updated calculations or specifications if
necessary.
104
MATERIALS EFFICIENCY MEASURES
MATERIALS EFFICIENCY MEASURES
Materials efficiency is one of the three main resource categories that comprise the EDGE standard. In order to
comply for certification purposes, the design and construction team must review the requirements for selected
measures as indicated and provide the information.
The following pages explain each materials efficiency measure by relaying the intention, approach, assumptions,
and compliance guidance requirements.
Figure 7. Screen shot of materials saving measures for hotels in EDGE
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MATERIALS EFFICIENCY MEASURES
HTM01 – FLOOR SLABS
Intention
To select a floor slab specification with a lower embodied energy than the typical specification.
Approach/Methodologies
The design team should select the specification that most closely resembles the floor slab specified, and enter
the thickness, which is a requirement of EDGE. Where there are multiple specifications the predominant
specification should be selected.
The specification for the floor slab should be that of the intermediary floor and not the ground floor, as the
ground floor slab is often dictated by the ground conditions.
Potential Technologies/Strategies
The following is a list of the specifications included in EDGE. The user should always try to select the
specification that most resembles that of the building design.
In-Situ Reinforced
Concrete Slab:
One of the most popular and conventional floor slab construction types, this floor
slab uses Portland cement, sand, aggregate, water, and reinforcing steel.
In-Situ Concrete with
>25% GGBS:
Ground granulated blast furnace slag (GGBS) is obtained by quenching molten
iron slag (a by-product of iron and steel making) from the blast furnace in water
or steam, producing a glassy, granular product which is then dried and ground
into a fine powder. EDGE estimates the embodied energy based on a 200mm
thickness.
The roof construction technology for GGBS is the same as for the in-situ reinforced
concrete slab but the Portland cement is directly replaced by industrial waste
(GGBFS) on a one-to-one basis by weight. Replacement levels of GGBS vary from
30% to up to 85% as applicable. In most instances typically 40% to 50% of GGBS
is used.
Since the manufacture of Portland cement is energy intensive, replacing it with
GGBS helps to reduce high-embodied energy content. Using GGBS also helps to
reduce air and water pollution, leading to a more sustainable roof construction
practice.
In-Situ Concrete with
>30% PFA:
Pulverized fuel ash (PFA), also known as fly ash, is a waste product of coal fired at
power stations. Using PFA as a cement replacement significantly reduces the
overall carbon footprint of the concrete construction and helps to reduce risk of air
and water pollution. In the promotion of environmental sustainability, PFA usage
is one of the most highly recommended construction practices.
Concrete Filler Slab:
Filler slab construction is technology based on the principal of using filler materials
such as brick, clay tiles, and cellular concrete blocks instead of concrete. The filler
materials are used in the lower tensile region of the slab, which needs only
enough concrete to hold the steel reinforcement together.
Filler slab uses less concrete as well as steel due to the lightweight quality of the
slab. It is also more cost-effective compared to conventional in-situ reinforced
concrete slab.
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MATERIALS EFFICIENCY MEASURES
This system uses precast concrete elements to construct intermediate floors and
consists of two elements:
Precast RC Planks and
Joist System:
The plank, which represents smaller sections of the slab and is therefore of
reduced thickness and reinforcement, and
The joist, which is a beam spanning across the room to provide a bearing for the
planks. The joist is partially precast, with the remaining portion being cast in-situ
after the planks are installed.
The monolithic action of the slab elements is enhanced by leaving reinforcement
hooks projecting out of the joists and providing nominal reinforcement over the
planks, before the in-situ concrete is poured. The planks are supported over
partially precast RC joists which are set side by side and then joined together by
pouring in-situ concrete over the entire roofing area. Both elements of the floor –
planks and joists – can be manually produced at the site using wooden moulds.
This method of construction saves time.
EDGE estimates the embodied energy based on a 150mm thickness.
Beam and Vault
with/without
Insulation:
This system is similar to concrete filler slab technology in that one of the aims is
to reduce the volume of concrete required, which is more cost-effective compared
to conventional in-situ reinforced concrete slab. It is comprised of precast
concrete beams, a polystyrene form which then stays in place, in the lower tensile
region of the slab and in-situ concrete.
This system can be installed with or without insulation. Adding insulation to the
floor slabs when they are exposed to outdoor or unconditioned area helps to
improve thermal performance for heat gain and loss. Using insulation reduces the
heating/cooling energy demand of the building. If Concrete Beam Vault with
Insulation is selected, then the embodied energy due to the insulation is added to
the floor slab in the Materials chart and not to the chart’s insulation section.
Relationship to Other Measures
The contribution that the measure makes to the overall performance is not affected by any other measure.
Assumptions
The base case assumption is that the floor will be constructed from 200mm in-situ reinforced concrete slab.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Floor sections showing build-up of the floor.
Manufacturer’s data sheet for specified building
material if applicable.
Bill of quantities with the floor slab specification
clearly highlighted.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Purchase receipt for the specified floor slab
material.
Delivery note.
Date stamped photographs of floor slabs taken
during or after construction.
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MATERIALS EFFICIENCY MEASURES
HTM02 – ROOF CONSTRUCTION
Intention
To select a roof specification with a lower embodied energy than the typical specification.
Approach/Methodologies
The design team should select the specification that most closely resembles the roof specified, and enter the
thickness, which is a requirement of EDGE. Where there are multiple specifications the predominant
specification should be selected.
Potential Technologies/Strategies
The following is a list of the specifications included in EDGE. The user should always try to select the
specification that most resembles that of the building design.
In-Situ Reinforced
Concrete Slab:
In-Situ Concrete with
>25% GGBS:
One of the most popular and conventional of all roof construction types, in-situ
reinforced concrete slab uses Portland cement, sand, aggregate, water, and
reinforcing steel.
Ground granulated blast furnace slag (GGBS) is obtained by quenching molten
iron slag (a by-product of iron and steel making) from the blast furnace in water
or steam, producing a glassy, granular product which is then dried and ground
into a fine powder.
The roof construction technology for GGBS is the same as for the in-situ reinforced
concrete slab but the Portland cement is directly replaced by industrial waste
(GGBS) on a one-to-one basis by weight. Replacement levels of GGBS vary from
30% to up to 85% as applicable. In most instances typically 40% to 50% of GGBS
is used.
Since the manufacture of Portland cement is energy intensive, replacing it with
GGBS helps to reduce high-embodied energy content. Using GGBS also helps to
reduce air and water pollution, leading to a more sustainable floor slab
construction practice.
In-Situ Concrete with
>30% PFA:
Pulverized fuel ash (PFA), also known as fly ash, is a waste product of coal fired
power stations. Using PFA as a cement replacement significantly reduces the
overall carbon footprint of the concrete construction and helps to reduce risk of air
and water pollution. In the promotion of environmental sustainability, PFA usage
is one of the most highly recommended construction practices.
Concrete Filler Slab:
Filler slab construction is technology based on the principal of using filler materials
such as brick, clay tiles, and cellular concrete blocks instead of concrete. The filler
materials are used in the lower tensile region of the slab, which needs only
enough concrete to hold the steel reinforcement together.
Precast RC Planks and
Joist System:
This system uses precast concrete elements to construct a roof or intermediate
floor and consists of two elements:
The plank, which represents smaller sections of the slab and is therefore of
reduced thickness and reinforcement, and
The joist, which is a beam spanning across the room to provide a bearing for the
planks. The joist is partially precast, with the remaining portion being cast in-situ
after the planks are installed.
The monolithic action of the slab elements is enhanced by leaving reinforcement
hooks projecting out of the joists and providing nominal reinforcement over the
planks, before the in-situ concrete is poured. The planks are supported over
partially precast RC joists which are set side by side and then joined together by
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108
MATERIALS EFFICIENCY MEASURES
pouring in-situ concrete over the entire roofing area. Both elements of the roof –
planks and joists – can be manually produced at the site using wooden moulds.
This method of construction saves time.
Clay Roofing Tiles on
Steel or Timber Rafters:
With this type of roof construction, clay tiles are laid on steel or timber rafters.
Steel rafters ensure durability and strength but the embodied energy content of
steel is higher than that of timber rafters, which need maintenance but have less
embodied energy. Timber sourced from a responsible forest management agency
or from re-growth forests ensures the protection and conservation of natural
forest communities. EDGE estimates the embodied energy based on a thickness of
10mm for the clay roofing tiles and 8mm for the steel or timber rafters.
Micro Concrete Tiles on
Steel Rafters and
Timber Rafters:
Micro Concrete Roofing (MCR) Tiles are a cost-effective, aesthetic, and durable
alternative sloping roof technology. They have less embodied energy content than
clay roof tiles and, as MCR tiles are lighter than other roofing tiles they can be laid
on a lighter weight structure.
Brick Panel Roofing
System:
Brick panel is made of first class bricks reinforced with two mild steel bars of 6mm
diameter with the joints filled with either 1:3 cement sand mortar or M15
concrete. The panels can be made in any size, but are typically 530mm x 900mm
or 530mm x 1200mm, depending on the requirements.
Beam and Vault
with/without
Insulation:
This system is similar to concrete filler slab technology in that one of the aims is
to reduce the volume of concrete required, which is more cost-effective compared
to conventional in-situ reinforced concrete slab. It is comprised of precast
concrete beams, a polystyrene form which then stays in place, in the lower tensile
region of the slab and in-situ concrete.
This system can be installed with or without insulation. Adding insulation to the
roof slabs helps to improve thermal performance for heat gain and loss. Using
insulation reduces the heating/cooling energy demand of the building. If “Concrete
Beam Vault with Insulation” is selected, then the embodied energy due to the
insulation is added to the roof slab in the Materials chart and not to the chart’s
insulation section.
Relationship to Other Measures
The selected roof specification will impact the thermal insulation of the roof surface, so the energy efficiency
could be adversely affected or improved by selecting different roof specifications.
Assumptions
The base case assumption is that the roof will be constructed from 200mm in-situ reinforced concrete slab.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



A section drawing of roof showing the materials
and thicknesses.
Manufacturer’s data sheet for specified building
material.
Bill of quantities with the materials used for roof
construction clearly highlighted.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Purchase receipt for the building materials used for
roof construction.
Delivery note for materials used for roof
construction.
Date stamped photograph of the roof taken during
or after construction.
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MATERIALS EFFICIENCY MEASURES
HTM03 – EXTERNAL WALLS
Intention
To select an external wall specification with a lower embodied energy than the typical specification.
Approach/Methodologies
The design team should select the specification that most closely resembles the external walls specified, and
enter the thickness, which is a requirement of EDGE. Where there are multiple specifications the predominant
specification should be selected.
The external walls of the building are those directly exposed to the outdoor environment.
Potential Technologies/Strategies
The following is a list of the specifications included in EDGE. Only the broad wall types are described here; EDGE
does not include options on plaster or finishing. The user should always try to select the specification that most
resembles that of the building design.
Common Bricks
Honeycomb Clay Blocks
Common bricks, also known as fired clay bricks, are usually the first choice of
builders as they are easily available and inexpensive. However, because
common bricks are fired at high temperatures, normally achieved by the
combustion of fossil fuels, they have a high embodied energy.
Honeycomb clay blocks are made of fired clay and have a honeycombed crosssection. The large size of the blocks enables rapid construction, and the
honeycomb structure means that there is less material per square meter of
finished wall. The features listed below make honeycomb clay blocks a more
eco-friendly building product:
The honeycomb structure leads to improved thermal performance.
Blocks can be customized.
No mortar is needed in the vertical joints due to a tongue and grooved edge,
reducing mortar use by up to 40%.
The blocks are strong and have a high impact resistance.
Honeycomb clay blocks have post-consumer value if dismantled carefully.
Medium Weight Hollow
Concrete Blocks
Hollow concrete blocks are lightweight and easier to handle than solid concrete
blocks. The lightness of the blocks helps in reducing the dead load of the
masonry on the structure. The voids also marginally improve the thermal
insulation and sound insulation of the block. The larger size of the blocks
(compared to conventional burnt clay bricks) also reduces the number of mortar
joints and the amount of cement mortar.
Solid Dense Concrete
Blocks
Solid dense concrete blocks can be used in virtually any part of a building. They
provide excellent sound insulation and their high strength makes them
applicable for use in structural walls. However, the use of virgin aggregates and
sand can lead to land or marine degradation and resource depletion, and the
lack of supplementary materials in the cement results in increased embodied
energy.
Autoclaved Aerated
Concrete Blocks
Aerated concrete is a versatile, lightweight building material. Compared to solid
dense concrete blocks, aerated concrete blocks have a lower density and
excellent insulation properties. They are durable and have good resistance to
sulfate attack and damage by fire and frost. Aerated concrete blocks are
excellent thermal insulators.
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MATERIALS EFFICIENCY MEASURES
Based on volume, the manufacture of aerated blocks typically uses 25% less
energy than other concrete blocks. They are lighter in weight which makes them
easier to work with and saves energy in transportation.
Fly-Ash Stabilized Soil
Blocks
Soil blocks have some inherent weaknesses that can be corrected using
stabilization materials like fly ash or ground granulated blast furnace slag
(GGBFS).
Fly ash usually refers to industrial waste produced during coal combustion.
Compressed Stabilized
Earth Blocks
Stabilized Compressed Earth Block (SCEB) technology offers a cost-effective and
environmentally-friendly alternative to conventional building materials. The
blocks are fire-resistant, provide better thermal insulation, and do not need to
be fired, so they have a lower embodied energy.
Ground Granulated Blast
(GGBS) Stabilized Soil
Blocks
GGBFS is a by-product of the iron industry. The molten slag is cooled rapidly
with water and is then ground into a fine cementations powder. GGBFS then can
be used as a cement replacement in the blocks.
Rammed Earth
Blocks/Walls
Precast Concrete Panels
Rammed earth walls are more commonly used in arid areas. They are
constructed by the compacting (ramming) of moistened subsoil into place
between temporary formwork panels. When dried, the result is a dense, hard
monolithic wall. As an alternative, rammed earth bricks are also available. The
high moisture mass of rammed earth helps regulate humidity.
Precast concrete is a construction product made by casting concrete in a
reusable molding or "form" which is then cured in a controlled environment,
transported to the construction site, and lifted into place.
Precast cladding or curtain walls are the most common use of precast concrete
for building envelopes. These types of precast concrete panels do not transfer
vertical loads but simply enclose the space. They are only designed to resist
wind, seismic forces generated by their own weight, and forces requiring
transferring the weight of the panel to the support. Common cladding units
include wall panels, window wall units, spandrels, mullions, and column covers.
These units can usually be removed individually if necessary.
In some cases, precast panels are used as formwork for cast-in-place concrete.
The precast panels act as a form, providing the visible aesthetics of the system,
while the cast-in-place portion provides the structural component.
Straw Bale Blocks
Straw bale blocks are a rapidly renewable building material made from the dry
stalk left in the earth after harvest, which is traditionally considered a waste
product that is burned or baled and sold for animal use. It is a natural, non-toxic
building material with low environmental impact and excellent insulation
properties. Since it is very easy to work with it is a good choice for amateur or
unskilled self-builders.
Straw bale houses are finished and coated with cement stucco or earth-based
plaster, sealing the straw from the elements and giving long-lasting protection
with little maintenance. In contrast to the timber used for wood framing, straw
can be grown in less than a year in a completely sustainable production system.
The conversion of straw into a sustainable renewable resource to be used as a
dominant building material could be especially beneficial in areas where the
climate is severe and timber is scarce, but straw is plentiful.
Timber Stud with
Insulation
Timber stud walls are a light weight construction technique which reduces the
dead load of building and increases the pace of construction.
Timber for stud walls should be made from local forest-department-certified
wood or a forest-stewardship-council-certified wood, which helps to avoid the
use of virgin wood for building construction activities.
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MATERIALS EFFICIENCY MEASURES
Phosphogypsum Panels
with Fibre Glass
Insulation
Phosphogypsum is a waste product of the fertilizer industry. The use of
phosphogypsum board in buildings is a substitute for natural gypsum.
Ferrocement Wall Panels
Ferrocement is a very simple construction of 2 to 5 layers of chicken wire over a
frame made from reinforcing bar, with cement forced into the gaps and in a
layer over the chicken wire reinforcing. The use of chicken wire makes
ferrocement a very flexible building material that is strongest when curved.
In-Situ Reinforced
Concrete Wall
More commonly used for floor slabs and roofs, in-situ reinforced concrete is also
used to construct external walls. It has a high embodied energy due to the
inclusion of Portland cement and also uses sand, aggregate, water, and
reinforcing steel.
Cellular Light Weight
Concrete Blocks
These blocks, which are environmentally friendly, are also called CLC blocks. The
energy consumed in the production is only a fraction compared to the production
of clay bricks. They are made from slurry of cement, fly ash*, and water, which
is further mixed with the addition of pre-formed stable foam in an ordinary
concrete mixer under ambient conditions.
The addition of foam to the concrete mixture creates millions of tiny voids or
cells in the material, hence the name Cellular Concrete.
*Fly ash is a waste material from thermal power plants.
Local Limestone Blocks
Limestone makes up about 10% of the total volume of all sedimentary rocks.
Although limestone is found widely, developers and designers should opt for
local extracted stone to reduce transport implications.
Limestone is readily available and relatively easy to cut into blocks in a quarry.
It is also long-lasting and stands up well to exposure, as it is hard, durable, and
commonly occurs in easily accessible surface exposures. As a stone it has a high
thermal inertia.
However, it is a very heavy material, making it impractical for tall buildings, and
relatively expensive as a building material.
FAL-G Block
The Fly Ash-Lime-Gypsum blocks technology primarily uses industrial wastes
such as fly ash (from thermal power plants), lime gypsum (from fertilizer
industries), and sand (optional) to produce alternative walling materials. It
reduces the environmental impacts associated with disposal of these industrial
wastes, as well as avoids the environmental impacts associated with clay brick
production, such as denudation of fertile topsoil. As the process for FAL-G blocks
does not require sintering, the amount of energy (fossil fuels) for production is
reduced.
The manufacturing process consists of three main stages:
-
Mixing the materials: Fly ash is mixed with lime and gypsum. Chemical
accelerator may or may not be added to it.
Pressing the mix in a machine: the mix is molded under pressure, also
air/ sun drying may be undertaken; and
Curing the blocks for a stipulated period: the green block is water
cured.
In the presence of moisture, fly ash reacts with lime at ordinary temperature
and forms a compound possessing cementations properties. After reactions
between lime and fly ash, calcium silicate hydrates are produced which are
responsible for the high strength of the compound.
Generally, FAL-G blocks are grey in color, solid, and have plain rectangular faces
with parallel sides and sharp straight and right-angled edges. They are also used
for development of infrastructure, construction of pavements, dams, tanks, and
under water works.
Steel Profile Cladding
Steel, one of the strongest and most affordable materials, is a ferrous metal,
meaning it contains iron. It has a favorable strength-to-weight ratio as well as
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MATERIALS EFFICIENCY MEASURES
provides elasticity. Other benefits include stiffness and fire and corrosion
resistance.
Steel wall cladding profiles create totally new economical solutions in both new
building and renovation and in operating and maintenance. The profiles are
versatile cladding that comes in a very broad range of shapes, finishing, and
colors that enable innovative designs. In addition, they can be installed with
insulation for better thermal performance.
Aluminum Profile
Cladding
Beside steel, aluminum is the most commonly used metal in construction. It is
one of the lightest and easiest metals to manipulate, bend, shape, cast, fasten,
and weld, and is also very ductile, often extruded into shapes for architectural
purposes. It can easily be drilled, tapped, sawed, planed, and filed with hand
tools, making it a yielding material for tradesmen to use.
Aluminum is commonly used as wall cladding or curtain-walls, as its resistance
to corrosion is higher than steel, and also lighter than other metals. However,
the disadvantages are the higher cost and embodied energy, greater thermal
expansion, and lower fire resistance as compared to steel.
Most exterior applications using aluminum alloys are anodized surfaces, which
increases the metal durability, traps dyes and adheres to other finishes. Plastic
coatings, which are applied electrostatically as a powder and then heat cured,
are also used for cladding wall panels. This coating gives a durable protection
layer, with a more uniform appearance.
The finished appearance can range from clear to a wide variety of colors and
textures, depending on the coating applied. In addition, the panels can be
installed with insulation for better thermal performance.
Relationship to Other Measures
The selected external wall specification will impact the thermal insulation of the external wall element, so the
energy efficiency could be adversely affected or improved by selecting different specifications.
Assumptions
The base case assumption is that the external wall will be constructed from 200mm common bricks.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:




Façade drawings clearly marking the external wall
specification selected.
Drawings of the external wall sections.
Manufacturer’s data sheet for specified building
material.
Bill of quantities with the materials used for the
external wall clearly highlighted.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Purchase receipt for the specified building materials
used for external walls construction.
Delivery note for materials used for external walls
construction.
Date stamped photograph of the external walls
taken during construction.
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MATERIALS EFFICIENCY MEASURES
HTM04 – INTERNAL WALLS
Intention
To select an internal wall specification with a lower embodied energy than the typical specification.
Approach/Methodologies
The design team should select the specification from the drop down list that most closely resembles the internal
walls specified, and enter the thickness, which is a requirement of EDGE. Where there are multiple
specifications the predominant specification should be selected.
Potential Technologies/Strategies
The following is a list of the specifications included in EDGE. Only the broad wall types are described here; EDGE
does not include options on plaster or finishing. The user should always try to select the specification that most
resembles that of the building design.
Common Bricks
Honeycomb Clay Blocks
Common bricks, also known as fired clay bricks, are usually the first choice of
builders as they are easily available and inexpensive. However, because common
bricks are fired at high temperatures, normally achieved by the combustion of
fossil fuels, they have a high embodied energy.
Honeycomb clay blocks are made of fired clay and have a honeycombed crosssection. The large size of the blocks enables rapid construction, and the
honeycomb structure means that there is less material per square meter of
finished wall. The features listed below make honeycomb clay blocks a more ecofriendly building product:
o
o
o
o
o
The honeycomb structure leads to improved thermal performance.
Blocks can be customized.
No mortar is needed in the vertical joints due to a tongue and grooved
edge, reducing mortar use by up to 40%.
The blocks are strong and have a high impact resistance.
Honeycomb clay blocks have post-consumer value if dismantled carefully.
Medium Weight Hollow
Concrete Blocks
Hollow concrete blocks are lightweight and easier to handle than solid concrete
blocks. The lightness of the blocks helps in reducing the dead load of the
masonry on the structure. The voids also marginally improve the thermal
insulation and sound insulation of the block. The larger size of the blocks
(compared to conventional burnt clay bricks) also reduces the number of mortar
joints and hence the amount of cement mortar.
Solid Dense Concrete
Blocks
Solid dense concrete blocks can be used in virtually any part of a building. They
provide excellent sound insulation and their high strength makes them applicable
for use in structural walls. However, the use of virgin aggregates and sand can
lead to land or marine degradation and resource depletion, and the lack of
supplementary materials in the cement results in increased embodied energy.
Autoclaved Aerated
Concrete Blocks
Aerated concrete is a versatile, lightweight building material. Compared to solid
dense concrete blocks, aerated concrete blocks have a lower density and
excellent insulation properties. They are durable and have good resistance to
sulphate attack and damage by fire and frost. Aerated concrete blocks are
excellent thermal insulators.
Based on volume, the manufacture of aerated blocks typically uses 25% less
energy than other concrete blocks. They are lighter weight which makes them
easier to work with and saves energy in transportation.
Fly-Ash Stabilized Soil
Blocks
Soil blocks have some inherent weaknesses that can be corrected using
stabilization materials like fly ash or ground granulated blast furnace slag
(GGBFS).
Fly ash usually refers to industrial waste produced during coal combustion.
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MATERIALS EFFICIENCY MEASURES
Compressed Stabilized
Earth Blocks
Stabilized Compressed Earth Block (SCEB) technology offers a cost-effective and
environmentally-friendly alternative to conventional building materials. The
blocks are fire-resistant, provide better thermal insulation, and do not need to be
fired, so they have a lower embodied energy.
Ground Granulated Blast
Furnace Slag (GGBS)
Stabilized Soil Blocks
GGBS is a by-product of the iron industry. The molten slag is cooled rapidly with
water and is then ground into a fine cementations powder. GGBFS then can be
used as a cement replacement in the blocks.
Rammed Earth
Blocks/Walls
Precast Concrete Panels
Rammed earth walls are more commonly used in arid areas. They are
constructed by the compacting (ramming) of moistened subsoil into place
between temporary formwork panels. When dried, the result is a dense, hard
monolithic wall. As an alternative, rammed earth bricks are also available. The
high moisture mass of rammed earth helps regulate humidity.
Precast concrete is a construction product made by casting concrete in a
reusable moulding or "form" which is then cured in a controlled environment,
transported to the construction site, and lifted into place.
Precast cladding or curtain walls are the most common use of precast concrete
for building envelopes. These types of precast concrete panels do not transfer
vertical loads but simply enclose the space. They are only designed to resist
wind, seismic forces generated by their own weight, and forces requiring
transferring the weight of the panel to the support. Common cladding units
include wall panels, window wall units, spandrels, mullions, and column covers.
These units can usually be removed individually if necessary.
In some cases, precast panels are used as formwork for cast-in-place concrete.
The precast panels act as a form, providing the visible aesthetics of the system,
while the cast-in-place portion provides the structural component.
Straw Bale Blocks
Straw bale blocks are a rapidly renewable building material made from the dry
stalk left in the earth after harvest, which is traditionally considered a waste
product that is burned or baled and sold for animal use. It is a natural, non-toxic
building material with low environmental impact and excellent insulation
properties. Since it is very easy to work it is a good choice for amateur or
unskilled self-builders.
Straw bale houses are finished and coated with cement stucco or earth-based
plaster, sealing the straw from the elements and giving long-lasting protection
with little maintenance. In contrast to the timber used for wood framing, straw
can be grown in less than a year in a completely sustainable production system.
The conversion of straw into a sustainable renewable resource to be used as a
dominant building material could be especially beneficial in areas where the
climate is severe and timber is scarce, but straw is plentiful.
Timber Stud Walls with
Insulation
Timber for stud walls should be made from local forest-department-certified
wood or a forest-stewardship-council-certified wood, which helps to avoid the
use of virgin wood for building construction activities.
Phosphogypsum Panels
with Fibre Glass
Insulation
Phosphogypsum is a waste product of the fertilizer industry. The use of
phosphogypsum board in buildings is a substitute for natural gypsum. However,
it may constitute an additional source of radiation exposure to both workers and
members of the public, both from the inhalation of radon progeny produced from
radon, which is exhaled from the plasterboard and from beta, and gamma
radiation produced by radioactive decay in the plasterboard.
Ferrocement Wall Panels
Ferrocement is a very simple construction of 2 to 5 layers of chicken wire over a
frame made from reinforcing bar, with cement forced into the gaps and in a layer
over the chicken wire reinforcing. The use of chicken wire makes ferrocement a
very flexible building material that is strongest when curved.
In-Situ Reinforced
Concrete Wall
More commonly used for floor slabs and roofs, in-situ reinforced concrete is also
used to construct walls. It has a high embodied energy due to the inclusion of
Portland cement and also uses sand, aggregate, water, and reinforcing steel.
Local Limestone Blocks
Limestone makes up about 10% of the total volume of all sedimentary rocks.
Although limestone is found widely, developers and designers should opt for local
extracted stone to reduce transport implications.
Limestone is readily available and relatively easy to cut into blocks in a quarry. It
is also long-lasting and stands up well to exposure, as it is hard, durable, and
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MATERIALS EFFICIENCY MEASURES
commonly occurs in easily accessible surface exposures. As a stone it has a high
thermal inertia.
However, it is a very heavy material, making it impractical for tall buildings, and
relatively expensive as a building material.
FAL-G Block
The Fly Ash-Lime-Gypsum blocks technology primarily uses industrial wastes
such as fly ash (from thermal power plants), lime gypsum (from fertilizer
industries), and sand (optional) to produce alternative walling materials. It
reduces the environmental impacts associated with disposal of these industrial
wastes, and avoids the environmental impacts associated with clay brick
production, such as denudation of fertile topsoil. As the process for FAL-G blocks
does not require sintering, the amount of energy (fossil fuels) for production is
reduced.
The manufacturing process consists of three main stages:
-
Mixing the materials: Fly ash is mixed with lime and gypsum. Chemical
accelerator may or may not be added to it.
Pressing the mix in a machine: the mix is molded under pressure, also
air/ sun drying may be undertaken; and
Curing the blocks for a stipulated period: the green block is water cured.
In the presence of moisture, fly ash reacts with lime at ordinary temperature and
forms a compound possessing cementations properties. After reactions between
lime and fly ash, calcium silicate hydrates are produced which are responsible for
the high strength of the compound.
Generally, FAL-G blocks are grey in color, solid, and have plain rectangular faces
with parallel sides and sharp, straight, and right angled edges. It is also used for
development of infrastructure, construction of pavements, dams, tanks, and
under water works.
Steel Profile Cladding
Steel, one of the strongest and most affordable materials, is a ferrous metal,
meaning it contains iron. It has a favorable strength-to-weight ratio as well as
provides elasticity. Other benefits include stiffness and fire and corrosion
resistance.
Steel wall cladding profiles create totally new economical solutions in both new
building and renovation and in operating and maintenance. The profiles are
versatile cladding that comes in a very broad range of shapes, finishing, and
colors that enable innovative designs. Also, insulation can be installed for better
thermal and acoustic performance.
Aluminum Profile
Cladding
Behind steel, aluminum is the most commonly used metal in construction. It is
one of the lightest and easiest metals to manipulate, bend, shape, cast, fasten,
and weld, and is also very ductile, often extruded into shapes for architectural
purposes. It can easily be drilled, tapped, sawed, planed, and filed with hand
tools, making it a yielding material for tradesmen to use.
Aluminum is commonly used as wall cladding or curtain-walls, as its resistance to
corrosion is higher than steel, and also lighter than other metals. However, the
disadvantages are the higher cost, greater thermal expansion, and lower fire
resistance as compared to steel.
For more durability and more uniform appearance, aluminum is anodized or
plastic coatings are applied. In this way, the finished appearance can range from
clear to a wide variety of colors and textures. Also, insulation can be installed for
better thermal and acoustic performance.
Relationship to Other Measures
The specification of internal walls does not affect other EDGE measures but can impact acoustic performance.
Assumptions
The base case assumption is that internal walls are constructed from 200mm common brick plastered on both
sides.
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MATERIALS EFFICIENCY MEASURES
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Drawings of the internal wall sections.
Manufacturer’s data sheet for building materials
used for internal wall specifications if available.
Bill of quantities with the materials used for the
internal wall clearly highlighted.
International Finance Corporation
Post-Construction Stage
At the post-construction stage one of the following
must be used to demonstrate compliance:



Purchase receipt for the specified building materials
used for internal walls construction.
Delivery note for materials used for internal walls
construction.
Date stamped photograph of the internal walls
taken during construction.
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MATERIALS EFFICIENCY MEASURES
HTM05 – FLOORING
Intention
To select a flooring specification with a lower embodied energy than the typical specification.
Approach/Methodologies
The design team should select the specification that most closely resembles the floor finish specified. Where
there are multiple specifications the predominant specification should be selected.
Potential Technologies/Strategies
Ceramic Tiles
The advantage of tiles is that they are hard wearing, which minimizes the
maintenance required. However, tiles are not maintenance free, as the grout
requires maintenance. The manufacture of tiles uses large amounts of energy
due to the firing required and therefore tiles have a high embodied energy.
Vinyl Flooring
Vinyl flooring is water resistant, low maintenance, and inexpensive. It is easy to
install and is durable. However, vinyl flooring has a high embodied energy and
can release harmful volatile organic compounds after installation. Although
durable, vinyl flooring must be laid on a flat, smooth surface. An uneven surface
might cause wearing and holes which are difficult to repair, as vinyl is usually
laid in a single piece.
Stone Tiles/Slabs
While stone tiles can often be sourced locally and have a low embodied energy,
they can be expensive.
Finished Concrete Floor
More commonly referred to as “screed,” cement plaster is often used as a
preparation layer for soft or flexible floor finishes or tiles. Cement plaster can be
used as a finish layer, but it can be chipped more easily than other hard flooring
options.
Linoleum Sheet
Linoleum, often referred to as lino, is a floor covering made from solidified
linseed oil (linoxyn), pine rosin, ground cork dust, wood flour, and mineral fillers
such as calcium carbonate. These materials are added to a canvas backing;
pigments are often added to the materials. Lino can be used as an alternative to
vinyl and has a much lower embodied energy.
Terrazzo Tiles
Terrazzo tiles are a hard-wearing option for flooring which require very little
maintenance. Terrazzo floors can be laid in situ by pouring concrete or resin with
granite chips and then polishing the surface. Alternatively, terrazzo tiles are
manufactured in a factory before being laid onsite.
Nylon Carpets
Most nylon carpets have a very high embodied energy because of the large
amount of energy used in their manufacture but also due to the fact that nylon is
made from oil. Nylon carpets have good acoustic properties and help to reduce
reverberation times as well as the transfer of impact sound.
Laminate Wooden
Flooring
Laminate wooden flooring is more dimensionally stable than solid wood flooring
so it can be used in rooms prone to changes in moisture levels or where
underfloor heating is used. Due to the thickness of the finish layer the number of
times that it can be refinished is reduced, but the initial capital cost is lower than
for solid wood flooring.
Terracotta Tiles
Terracotta is fine-grained, orange, or reddish-brown fired clay that is used for
several construction and decorative purposes, mainly roof and floor tiles. The
name comes from Italian, which means "baked earth", as it is literally cooked or
fired earth or soil.
The color varies slightly depending on the clay used. It is waterproof and a very
sturdy material. Its durability and resistance to both fire and water make it an
ideal building material. It is also lighter than stone, and it can be glazed for extra
durability or to provide a wide variety of colors, including finishes that resemble
stone or metal patina. Terracotta is a relatively inexpensive material.
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MATERIALS EFFICIENCY MEASURES
Relationship to Other Measures
Although flooring does not affect other EDGE measures it can impact acoustic performance.
Assumptions
The base case assumption is that ceramic tile flooring is specified.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Drawings clearly marking the flooring specification
selected.
Manufacturer’s data sheet for building materials
used for floor specifications.
Bill of quantities with the materials used for the
flooring clearly highlighted.
International Finance Corporation
Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Purchase receipt for the specified building materials
used as a floor finish.
Delivery note for materials used for flooring.
Date stamped photograph of the flooring once
fitted.
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MATERIALS EFFICIENCY MEASURES
HTM06 – WINDOW FRAMES
Intention
To select a window frame specification with a lower embodied energy than the typical specification.
Approach/Methodologies
The design team should select the specification that most closely resembles the windows specified. Where there
are multiple specifications the predominant specification should be selected.
Potential Technologies/Strategies
The following is a list of the specifications included in EDGE. The user should always try to select the
specification that most resembles that of the building design.
Metal Frames
-
Aluminum
- Steel
The advantage of using metal window frames is that they are strong, light, and
require less maintenance than other materials used for window frames. However
as metal conducts heat very well, the thermal performance of metal windows is
not as good as other materials. To reduce heat flow and the U Value, metal
frames can include a thermal break between the inside and outside of the frame.
The two metals typically used for window frames are aluminum or steel.
Aluminum is lighter weight and does not rust like a ferrous metal such as steel,
but the embodied energy is much higher. Steel windows are heavier and require
some maintenance to protect from rust (unless stainless steel is used).
Timber Frames
Timber window frames insulate relatively well, but they also expand and contract
in response to weather conditions. Timber frames can be made from either
softwood or hardwood. Softwood frames are much cheaper, but are likely to
require more regular maintenance. The maintenance required can be reduced by
using aluminum or vinyl cladding.
uPVC
uPVC window frames are made of extruded polyvinyl chloride (PVC) with
ultraviolet light (UV) stabilizers to keep sunlight from breaking down the material.
uPVC window frames are low maintenance as they do not require painting. If the
cavities of uPVC frames are filled with insulation, they have very good thermal
performance.
Relationship to Other Measures
The choice of window frame material will have an impact on thermal performance. EDGE does not directly take
account of this as it is already reflected in the manufacturer’s calculation of the window U Value.
Assumptions
The default assumption is that window frames are aluminum.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Façade drawings clearly marking the window
frame(s) specification.
Manufacturer’s data sheet for glazing specified.
Bill of quantities with the windows/window frames
clearly highlighted.
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



Purchase receipt for the specified window.
Delivery note for windows.
Date stamped photograph of the installed windows.
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MATERIALS EFFICIENCY MEASURES
HTM07 & HTM08 – INSULATION
Intention
To select insulation with a low embodied energy.
Approach/Methodologies
The design team should select the specification that most closely resembles the insulation specified. Where
there are multiple specifications the predominant specification should be selected.
As the base case assumes that no insulation is specified the embodied energy calculation will not take account
of the insulation selected unless the Insulation of Roof Surface (HTE03) and/or Insulation of External Walls
(HTE04) measures are selected in the energy efficiencies section.
Potential Technologies/Strategies
Polystyrene
Polystyrene has the highest embodied energy per square meter of any other
insulation type. There are two types of polystyrene insulation:


Expanded Polystyrene (EPS) insulation is made from small beads of polystyrene
that when heated cause them to expand; they are then mixed with a blowing
agent (pentane). Expanded polystyrene is available in board form or as beads.
Boards are produced by placing the beads in moulds and heating them in order
to fuse the beads together. Typical applications of EPS boards are for insulation
of walls, roofs, and floors. Polystyrene beads are frequently used as cavity fill in
masonry walls.
Extruded Polystyrene (XPS) is made by mixing polystyrene with a blowing agent
under pressure and forcing it through a die. As it emerges from the die it
expands into foam; it can then be shaped and trimmed. XPS is slightly stronger
than EPS, and although it is used in many of the same applications as EPS, it is
particularly suitable for use below ground or where extra loading and/or impacts
might be anticipated.
Mineral Wool
Rock-based mineral wool is made by melting rock and recycled steel slag and
spinning it into fibers. The insulation is available in different densities depending on
the required functionality. Higher densities provide better sound insulation but poorer
thermal insulation. Applications include masonry cavity walls, timber frame walls,
and insulation for roof rafters, lofts, and suspended floors. Mineral wool has low
resistance for moisture.
Glass Wool
Glass wool insulation is manufactured in a similar way to rock wool, though the raw
materials are different as well as the melting process. Glass wool is made from silica
sand, recycled glass, limestone, and soda ash. Higher densities provide better sound
insulation but poorer thermal insulation. Applications include masonry cavity walls,
timber frame walls, and insulation for roof rafters, lofts, and suspended floors.
Polyurethane
Polyurethane (PUR), a closed-cell plastic, is formed by reacting two monomers in the
presence of a blowing agent catalyst (polymerisation). Polyisocyanurate foam (PIR) is
essentially an improvement on polyurethane (there is a slight difference in the
constituents and the reaction is conducted at higher temperatures). PIR is more fireresistant and has a slightly higher R Value.
Applications include wall, floor, and roof insulation. Polyurethane is also popular in
laminate form in SIPS and as an insulation backing to rigid boarding such as
plasterboard.
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MATERIALS EFFICIENCY MEASURES
Relationship to Other Measures
The base case assumes that no insulation is used. If the measures for roof surface and/or external walls
insulation are selected then the improved case will assume that polystyrene insulation is specified. If either
mineral wool or glass wool is selected on the insulation dropdown, it will result in a small percentage
improvement over the base case, due to the greater embodied energy in polystyrene insulation.
Assumptions
The base case assumption is that no insulation is specified. The improved case assumes that polystyrene
insulation is specified.
Compliance Guidance
Design Stage
At the design stage the following must be used to
demonstrate compliance:



Drawings clearly marking the insulation
specification selected.
Manufacturer’s data sheet for insulation specified.
Bill of quantities with the insulation materials
clearly highlighted.
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Post-Construction Stage
At the post-construction stage the following must be
used to demonstrate compliance:



An invoice for the specified insulation.
Delivery note for materials used for insulation.
Date stamped photograph of the insulation installed
during construction.
122
REFERENCES
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APPENDIX
APPENDIX 1: COUNTRY SPECIFIC CONSIDERATIONS
Currently there are no country specific considerations under hotels in EDGE.
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