Non-Domestic Building Services Compliance Guide

Non-Domestic Building Services Compliance Guide
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Non-Domestic Building Services
Compliance Guide
2013 edition – for use in England*
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* Note: Any reference to the Building Regulations in this guide is to the Building Regulations 2010 in
England (as amended). These Regulations also apply to the following building work in Wales:
(a) work on an excepted energy building as defined in the Schedule to the Welsh Ministers
(Transfer of functions) (No 2) Order 2009 (SI 2009/3019); and
(b) work that is subject to provisions of the regulations relating to energy efficiency specified
in regulation 34 of the Regulations and is carried out to educational buildings, buildings of
statutory undertakers and Crown buildings, or carried out by Crown authorities.
This guidance comes into effect on 6 April 2014. Work started before this date remains subject to
the earlier edition of the guidance. Work subject to a building notice, full plans application or initial
notice submitted before this date will also remain subject to the earlier edition of the guidance,
provided it is started before 6 April 2015.
For other jurisdictions in the UK, it will be necessary to consult their own building regulations and
guidance.
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Contents
Contents
Section 1:
Section 2:
Section 3:
Section 4:
Introduction
5
1.1
Scope
5
1.2
Innovative systems
6
1.3
European directives
6
1.4
Status of guide
7
1.5
How to use this guide
8
1.6
Key terms for space heating and domestic hot water systems
8
1.7
Summary of recommended minimum energy efficiency standards
9
Gas, oil and biomass-fired boilers
14
2.1
Introduction
14
2.2
Scope of guidance
14
2.3
Key terms 14
2.4 Determining boiler seasonal efficiency
16
2.5
19
Boilers in new buildings
2.6 Boilers in existing buildings
20
2.7
21
Heating efficiency credits for replacement boilers
2.8 Biomass boilers
24
Heat pumps 25
3.1
Introduction
25
3.2
Scope of guidance
25
3.3
Key terms
26
3.4
Heat pumps in new and existing buildings
26
3.5
Heating efficiency credits for heat pump systems in existing buildings
28
3.6
Supplementary information
30
Gas and oil-fired warm air heaters 31
4.1
Introduction 31
4.2
Scope of guidance
31
4.3
Key terms
31
4.4 Warm air heaters in new and existing buildings 32
4.5
32
Heating efficiency credits for warm air heaters in new and existing buildings ONLINE VERSION
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Non-Domestic Building Services Compliance Guide: 2013 Edition
Section 5:
Section 6:
Section 7:
Section 8:
Gas and oil-fired radiant heaters 34
5.1
Introduction
34
5.2
Scope of guidance
34
5.3
Key terms
34
5.4
Radiant heaters
35
5.5
Heating efficiency credits for radiant heaters in existing buildings 35
Combined heat and power and community heating 37
6.1
Introduction
37
6.2 Scope of guidance
37
6.3
37
Key terms 6.4 CHP in new and existing buildings 38
6.5 Supplementary information
39
Direct electric space heating 40
7.1
Introduction 40
7.2
Scope of guidance
40
7.3
Electric space heating in new and existing buildings 40
Domestic hot water 43
8.1
Introduction 43
8.2 Scope of guidance
43
8.3
44
Key terms
8.4 Domestic hot water systems in new and existing buildings
46
8.5 Supplementary information on electric water heaters
48
8.6 Heating efficiency credits for domestic hot water systems in new and existing
buildings
49
Section 9:
2
Comfort cooling 51
9.1
Introduction 51
9.2
Scope of guidance 51
9.3
Key terms
51
9.4
Comfort cooling in new and existing buildings
52
9.5
Calculating the seasonal energy efficiency ratio for SBEM 53
9.6
Supplementary information
55
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Section 10:
Section 11:
Section 12:
Section 13:
Contents
Air distribution 56
10.1 Introduction
56
10.2 Scope of guidance
56
10.3 Key terms
56
10.4 Air distribution systems in new and existing buildings 57
10.5 Heat recovery in air distribution systems in new and existing buildings 61
10.6 Calculating the specific fan power for SBEM
61
Pipework and ductwork insulation 62
11.1
Introduction
62
11.2 Scope of guidance 62
11.3 Insulation of pipes and ducts in new and existing buildings 62
Lighting 65
12.1 Introduction
65
12.2 Scope of guidance
65
12.3 Key terms
65
12.4 Lighting in new and existing buildings
66
12.5 Lighting Energy Numeric Indicator (LENI)
68
Heating and cooling system circulators and water pumps 71
13.1 Introduction
71
13.2 Scope of guidance
71
13.3 Key terms
71
13.4 Glandless circulators and water pumps in new and existing buildings
71
13.5 Supplementary information
71
Appendix A: Abbreviations
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Section 1: Introduction
Section 1: Introduction
1.1 Scope
This guide provides detailed guidance for the installation of fixed building services in new and existing nondomestic buildings to help compliance with the energy efficiency requirements of the Building Regulations.
This edition covers the design, installation and commissioning of:
• conventional means of providing primary space heating, domestic hot water, mechanical ventilation,
comfort cooling and interior lighting
• low carbon generation of heat by heat pumps and combined heat and power systems.
The guide sets out recommended minimum energy efficiency standards for components of building
services systems, including the use of controls. For systems installed in new buildings, the standards are
design limits (or backstop values). For new or replacement systems and components installed in existing
buildings, the standards represent reasonable provision for complying with the Building Regulations.
It is important to note that standards higher than many of these recommended minimum standards will
need to be achieved if:
• new buildings are to meet the the Building Regulations target carbon dioxide emission rate (TER)
calculated using National Calculation Methodology (NCM) tools such as SBEM1
• systems (up to 45 kW heat output) are to comply with the Microgeneration Certification Scheme
standards that enable building owners to receive payments under the Renewable Heat Incentive (RHI)
and qualify for Green Deal funding
• products are to be recognised as renewable technologies under the Renewable Energy Directive.
The guide includes some supplementary information that identifies good practice design and installation
standards that exceed the minimum standards in this guide. Microgeneration Certification Scheme
standards2 are an example of good practice standards.
In relevant sections, the guide identifies additional non-prescriptive measures (for example additional
controls) that can improve plant efficiency. These may be used to gain ‘heating efficiency credits’ to
help meet the carbon dioxide emission targets for new buildings, or the recommended minimum energy
efficiency standards set out in this guide for work in existing buildings.
A summary of recommended minimum energy efficiency standards is presented in Table 1 at the end of
this section.
1
2
The National Calculation Methodology (NCM) modelling guide and the Simplified Building Energy Model (SBEM) tool can be downloaded from www.ncm.bre.co.uk.
http://www.microgenerationcertification.org/mcs-standards
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1.2 Innovative systems
It is also important to note that this guide covers a range of frequently occurring situations. It deals
with the most commonly used fixed building services technologies. In doing so it neither endorses
these methods and technologies nor excludes other more innovative technologies that may offer an
alternative means of meeting the functional requirements of the Building Regulations.
Where the alternative technology has been the subject of a recognised testing procedure that assesses
its energy performance, this may be used to indicate that the system is adequately efficient. In the event
that there is no recognised testing standard, suitable calculations or modelling methods may be used to
show the carbon performance of the system.
1.3 European directives
The design and installation of fixed building services products, such as boilers, circulators and heat
pumps, shall at the appropriate time comply with all relevant requirements of EU directives as
implemented in the United Kingdom. There are a number of directives with requirements that directly or
indirectly control the energy efficiency of building services.
The Ecodesign Directive 2009/125/EC provides a framework for establishing requirements for ‘energyrelated’ products placed on the EU market. Current requirements cover ‘energy-using’ products such as
boilers, light bulbs and washing machines. In the future, requirements will also cover products such as
windows, insulation material and shower heads whose use has an impact on energy consumption.
The requirements are set out in Commission Regulations listed in the document http://ec.europa.eu/energy/
efficiency/ecodesign/doc/overview_legislation_eco-design.pdf. Products covered by the regulations can only
be CE marked and placed on the market if they meet the ecodesign standards specified.
At the time of preparation of this guide, Commission Regulations existed or were being developed for:
• space heaters and combination heaters
• water heaters and hot water storage tanks
• glandless standalone circulators and glandless circulators integrated in products
• water pumps
• air conditioners and comfort fans
• fans driven by motors with an electric input power between 125 W and 500 kW
• lighting products in the domestic and tertiary sectors
• electric motors.
The intention is that the recommended minimum product standards in this guide should at least match the
energy efficiency standards set out in Commission Regulations as they come into force. For example, although
the implementing regulations for hot water storage tanks were published in September 2013, the standards do
not come into force until September 2017.
If in any doubt as to whether a product is subject to minimum ecodesign standards, check the
Commission document above.
The Energy Labelling Directive 2010/30/EU complements the Ecodesign Directive by providing
a framework for labelling of energy-related products including lamps, luminaires, household air
conditioners and washing machines. The Energy Label classifies products on an A to G scale, ‘pulling’
the market towards more efficient products by better informing consumers. The Ecodesign Directive, by
contrast, uses regulation to ‘push’ the market away from the worst performing products.
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Section 1: Introduction
The Renewable Energy Directive 2009/28/EC provides a framework for the promotion of energy from
renewable resources. It sets a mandatory UK target of 15% energy generation from renewable sources by
2020 – the ‘renewable energy obligation’ – as a contribution to meeting the EU’s overall target of 20%.
Of relevance to building services is that it includes criteria for training and certification of installers of
renewables. The directive also specifies in Annex VII the standards that heat pumps must achieve to be
recognised as renewable technologies by the directive.
The Energy Efficiency Directive 2012/27/EU establishes a common framework of measures for the
promotion of energy efficiency within the EU in order to ensure that the EU meets its target of a 20%
reduction in primary energy consumption by 2020. Legislation to implement the directive in the UK
will be published by 5 June 2014. Included will be requirements for public authorities to purchase only
energy-efficient products, services and buildings; and requirements for heat meters to be fitted in
apartments and buildings connected to a central source of heating or district heating network. For more
information on the specific requirements and technical standards, see the DECC website3.
The Energy Performance of Buildings Directive 2010/31/EU is a recast of the original 2002/91/EC
directive, which in 2002 introduced requirements for:
• the establishment of a methodology for calculating the integrated energy performance of buildings
• minimum energy performance requirements for new buildings, and, where feasible, for larger
buildings undergoing major renovation
• energy performance certification of buildings, and
• inspections of heating and air conditioning systems.
The recast directive includes a new requirement to consider, in the design of new buildings, the
feasibility of using renewables and other ‘high-efficiency alternative systems’. There is no mandatory
format for this assessment, but it will now be necessary to declare (through a new field in the energy
performance calculation software) that it has been carried out.
The Building Regulations, which already met the original requirements in many ways (for example by
setting standards for new buildings), have been amended in some places to reflect the new requirements
of the directive. For guidance on the changes affecting new buildings, see Approved Document L2A.
For guidance on the changes affecting major renovations, see Approved Document L2B. For guidance
on other requirements relating to building certification and inspection of heating and air conditioning
systems, see the DCLG website4.
1.4 Status of guide
The Building Regulations contain functional requirements, such as requirements that buildings must
be structurally stable, constructed and fitted to ensure fire protection, and energy efficient. These
functional requirements are often drafted in broad terms, and so it may not always be immediately
clear to a person carrying out work how to comply with the relevant requirements. Consequently, the
Department for Communities and Local Government issues documents, known as approved documents,
which provide practical guidance on ways of complying with specific aspects of the Building Regulations
in some of the more common building situations.
Approved documents are not always comprehensive and may contain references to other documents
which will provide more detailed information and assistance on parts of the guidance. This guide is one
of those documents: it provides more detailed information on the guidance contained in Approved
3
4
https://www.gov.uk/decc
https://www.gov.uk/dclg
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Documents L2A and L2B about compliance with the energy efficiency requirements which apply when
installing fixed building services in new and existing buildings.
If you follow the relevant guidance in an approved document, and in any document referred to in the
approved document (such as this guide) which provides additional information to help you follow that
guidance, there is a legal presumption that you have complied with the Building Regulations. However, in
each case it is for the building control body (local authority or approved inspector) to decide whether
work complies with the requirements of the Building Regulations. It is therefore sensible that you check
with the building control body before starting work what they consider it is necessary for you to do to
comply with the requirements of the Building Regulations.
1.5 How to use this guide
The guide is divided into the following sections:
Section 1: Introduction and summary of energy efficiency standards
Section 2: Gas, oil and biomass-fired boilers
Section 3: Heat pumps
Section 4: Gas and oil-fired warm air heaters
Section 5: Gas and oil-fired radiant heaters
Section 6: Combined heat and power and community heating
Section 7: Direct electric space heating
Section 8: Domestic hot water
Section 9: Comfort cooling
Section 10: Air distribution
Section 11: Pipework and ductwork insulation
Section 12: Lighting
Section 13: Heating and cooling system circulators and water pumps
Supplementary information is shown against a blue background. This may be further information to help with interpreting the minimum energy efficiency provisions needed to comply with the Building Regulations. Or it may be guidance on best practice that goes beyond the recommended
minimum standards.
Key terms are printed in blue and are defined at appropriate points throughout the guide.
1.6 Key terms for space heating and domestic hot water systems
The following general definitions are applicable to the sections that deal with space heating and hot
water. Further definitions are included in later sections as appropriate.
Heat generator means a device for converting fuel or electricity into heat – e.g. a boiler or radiant heater.
Heat generator efficiency means the useful heat output divided by the energy input in the fuel (based on
gross calorific value) or electricity delivered to the heat generator, as determined by the appropriate test
methods for that type of heat generator.
Heat generator seasonal efficiency means the estimated seasonal heat output from the heat generator
divided by the energy input. This will depend on the heat generator efficiency and the operating mode
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Section 1: Introduction
of the heat generator over the heating season. For example, in the case of boilers it is a ‘weighted’
average of the efficiencies of the boiler at 30% and 100% of the boiler output. For other technologies the
heat generator seasonal efficiency may be the same as the heat generator efficiency.
Minimum controls package means a package of controls specific to each technology that represents
the recommended minimum provision necessary to meet the Building Regulations energy efficiency
requirements.
Additional measures means additional controls or other measures that go beyond the recommended
minimum controls package and for which heating efficiency credits are available.
Heating efficiency credits are awarded for the provision of additional measures, such as additional
controls, that raise the energy efficiency of the system and go beyond recommended minimum
standards. Different credits apply to the different measures that are available for heating and hot water technologies.
Effective heat generator seasonal efficiency is obtained by adding heating efficiency credits, where
applicable, to the heat generator seasonal efficiency:
Effective heat generator seasonal efficiency =
heat generator seasonal efficiencyheating efficiency credits
Equation 1
Where relevant, this guide sets standards for effective heat generator seasonal efficiency so that a heat
generator with an inherently low efficiency may be used in combination with additional measures.
Space heating system means the complete system that is installed to provide heating to the space. It
includes the heating plant and the distribution system by which heating is delivered to zones. Heat losses
from the distribution system can be addressed by reference to guidance by TIMSA on HVAC insulation5.
Domestic hot water system means a local or central system for providing hot water for use by building
occupants.
1.7 Summary of recommended minimum energy efficiency standards
Unless specified otherwise in this guide, it is recommended that, where applicable, building services are
provided with controls that as a minimum correspond to Band C in BS EN 15232:2012 Energy performance
of buildings. Impact of building automation, controls and building management.
5
TIMSA HVAC guidance for achieving compliance with Part L of the Building Regulations at www.timsa.org.uk
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Table 1 Recommended minimum energy efficiency standards for building services6
Gas, oil and biomass-fired boilers:
new buildings
Seasonal efficiency (gross7)
Natural gas
Single-boiler system  2 MW output
91%
Single-boiler system  2 MW output
86%
Multiple-boiler system
82% for any individual boiler
86% for overall multi-boiler system
Single-boiler system  2 MW output
93%
Single-boiler system  2 MW output
87%
Multiple-boiler system
82% for any individual boiler
87% for overall multi-boiler system
Single-boiler system
84%
Multiple-boiler system
82% for any individual boiler
84% for overall multi-boiler system
LPG
Oil
Biomass – independent, automatic, pellet/woodchip
75%
Seasonal efficiency (gross)
Gas, oil and biomass-fired boilers:
existing buildings
Actual
Effective
Natural gas
82%
84%
LPG
83%
85%
Oil
84%
86%
Biomass – independent, automatic, pellet/woodchip
Heat pump units
75%
Coefficient of performance (COP)
Air-to-air
Space heating  12 kW
Seasonal COP ‘D’ rating for median temperature
range in BS EN 148258
All others except absorption and
gas-engine
Space heating
2.5 (250%) at rating conditions in BS EN 145119
Domestic hot water
2.0 (200%) at rating conditions in BS EN 14511
Absorption
0.5 (50%) when operating at the rating
conditions
Gas-engine
1.0 (100%) when operating at the rating
conditions
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10
Emerging European regulations implementing the Ecodesign Directive set minimum standards for the efficiency of energy-using products that can be placed on the market. Products
should also comply with these standards as they come into effect. Current regulations are listed at http://ec.europa.eu/energy/efficiency/ecodesign/doc/overview_legislation_ecodesign.pdf.
Efficiency is heat output divided by calorific value of fuel. The net calorific value of a fuel excludes the latent heat of water vapour in the exhaust, and so is lower than the gross
calorific value. Efficiency test results and European standards normally use net calorific values.
Seasonal coefficient of performance (SCOP) is the current Ecodesign Directive measure for space heating air-to-air heat pumps with an output of up to 12 kW. Eventually, the measure
used will be the seasonal primary energy efficiency ratio (SPEER), with testing and rating to BS EN 14825:2013 Air conditioners, liquid chilling packages and heat pumps with electrically
driven compressors for space heating and cooling. Testing and rating at part load conditions and calculation of seasonal performance. Energy labelling with the SPEER rating will be
mandatory from 2015.
Rating conditions are standardised conditions provided for the determination of data presented in BS EN 14511:2013 Air conditioners, liquid chilling packages and heat pumps with
electrically driven compressors for space heating and cooling.
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Section 1: Introduction
Table 1 Recommended minimum energy efficiency standards for building services (continued)
Gas and oil-fired warm air systems
Thermal efficiency (net)
Gas-fired forced convection (natural gas)
91%
Gas-fired forced convection (LPG)
91%
Direct gas-fired forced convection
100%
Oil-fired forced convection
91%
Efficiency (net)
Radiant heaters
Thermal
Radiant
Luminous radiant heater (unflued)
86%
55%
Non-luminous radiant heater (unflued)
86%
55%
Non-luminous radiant heater (flued)
86%
55%
Multi-burner radiant heater
91%
N/A
Combined heat and power (CHP)
CHPQA quality index
Power efficiency
All types
105
20%
Electric (primary) heating
Seasonal efficiency
Boiler and warm air
N/A
Heat generator seasonal efficiency (gross)
Domestic hot water systems
Thermal efficiency
Direct-fired:
new buildings
Natural gas  30 kW output
90%
Natural gas  30 kW output
73%
LPG  30 kW output
92%
LPG  30 kW output
74%
Oil
76%
Natural gas
73%
LPG
74%
Oil
75%
Direct-fired: existing
buildings
Indirect-fired
(dedicated hot water
boiler)*:
new and existing
buildings
Boiler seasonal
efficiency
Natural gas
80%
LPG
81%
Oil
82%
*See Table 26 for method of calculating efficiency for primary return temperatures  or  55°C.
Electrically-heated: new and existing buildings
N/A
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Table 1 Recommended minimum energy efficiency standards for building services (continued)
Comfort cooling systems
Energy efficiency ratio (EER)
Packaged air conditioners – single-duct types
2.6
Packaged air conditioners – other types
2.6
Split and multi-split air conditioners  12 kW
2.6
Split and multi-split air conditioners  12 kW
SCOP ‘D’ rating for median temperature range
in BS EN 14825
Variable refrigerant flow systems
2.6
Vapour compression cycle chillers, water cooled  750 kW
3.9
Vapour compression cycle chillers, water cooled  750 kW
4.7
Vapour compression cycle chillers, air cooled  750 kW
2.55
Vapour compression cycle chillers, air cooled  750 kW
2.65
Water loop heat pump
3.2
Absorption cycle chillers
0.7
Gas-engine-driven variable refrigerant flow
1.0
Specific fan power (SFP)10 (W/(l.s))
Air distribution systems
New
buildings
Existing buildings
Central balanced mechanical ventilation system with heating and cooling
1.6
2.2
Central balanced mechanical ventilation system with heating only
1.5
1.8
All other central balanced mechanical ventilation systems
1.1
1.6
Zonal supply system where fan is remote from zone, such as ceiling void
or roof-mounted units
1.1
1.4
Zonal extract system where fan is remote from zone
0.5
0.5
Zonal supply and extract ventilation units, such as ceiling void or roof
units serving a single room or zone with heating and heat recovery
1.9
1.9
Local balanced supply and extract ventilation system, such as wall/roof
units serving single area with heating and heat recovery
1.6
1.6
Local supply or extract ventilation units such as window/wall/roof units
serving single area (e.g. toilet extract)
0.3
0.4
Other local ventilation supply or extract units
0.5
0.5
Fan-assisted terminal VAV unit
1.1
1.1
Fan coil units (rating weighted average)
0.5
0.5
Kitchen extract, fan remote from zone with grease filter
1.0
1.0
10
12
Maximum pressure drop is not specified.
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Section 1: Introduction
Table 1 Recommended minimum energy efficiency standards for building services (continued)
Air distribution systems: new and existing buildings
Dry heat recovery efficiency
Plate heat exchanger
50%
Heat pipes
60%
Thermal wheel
65%
Run around coil
45%
Internal lighting: option 1
Effective lighting efficacy
General lighting in office, storage and industrial areas
60 luminaire lumens per circuit-watt
General lighting in other types of space
60 lamp lumens per circuit-watt
Display lighting
22 lamp lumens per circuit-watt
Internal lighting: option 2
Lighting Energy Numeric Indicator (LENI)
Lighting system
 lighting energy limit (kWh/m2/year)
specified in Table 44
Heating system circulators and water pumps
Energy Efficiency Index
Glandless standalone circulators
Glandless, standalone and integrated circulators
 0.27 until 31 July 2015
 0.23 from 1 August 2015
Water pumps
See Section 13
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Section 2:Gas, oil and biomass-fired boilers
2.1 Introduction
This section provides guidance on specifying gas, oil and biomass-fired space heating systems for new
and existing buildings to meet relevant energy efficiency requirements in the Building Regulations. It
covers relevant boiler types, and describes measures, such as additional controls, that can be used to
gain heating efficiency credits to improve the heat generator seasonal efficiency.
2.2 Scope of guidance
The guidance applies to wet central heating systems using commercial boilers fired by:
• natural gas
• liquid petroleum gas (LPG)
• oil, and
• biomass.
The guidance in this section does not cover:
• steam boilers (as these are used primarily for processes rather than provision of space heating), or
• electric boilers (for which see Section 7).
2.3 Key terms
The terminology used to describe efficiencies for boiler systems is detailed below. In this section the
heat generator is a boiler.
Biomass means all material of biological origin, excluding material embedded in geological formations
and transformed to fossil fuel.
Boiler efficiency means the energy delivered by the water as it leaves the boiler (or boilers in multi-boiler
installations) to supply the heat emitters, divided by the energy (based on gross calorific value) in the
fuel delivered to the boiler, expressed as a percentage. It is an expression of the boiler’s performance and
excludes energy used by boiler auxiliary controls, pumps, boiler room ventilation fans, mechanical flue
extraction fans and fan dilution systems. The boiler efficiency is measured according to the standards
that are used to demonstrate compliance with the Boiler Efficiency Directive11.
Effective boiler seasonal efficiency is the boiler seasonal efficiency (as calculated by Equation 2 below for
individual boilers, or by Equation 3.1 for multiple boilers), plus any applicable heating efficiency credits.
Economiser means a device, including a secondary heat exchanger fitted on or near to a boiler, which
provides additional heat transfer capacity. For the purposes of this guide, any boiler which will be
supplied with an economiser should have the economiser fitted when the boiler efficiency is tested
according to the standards that are used to demonstrate compliance with the Boiler Efficiency Directive.
The effect of this on the boiler efficiency at 30% and 100% of the boiler output may be taken into
11
14
Council Directive 92/42/EEC (the Boiler Efficiency Directive) relates to the efficiency requirements for new hot water boilers fired with liquid or gaseous fuels. The associated UK
legislation is the Boiler (Efficiency) Regulations 1993 (SI 1993/3083), amended by the Boiler (Efficiency) (Amendment) Regulations 1994 (SI 1994/3083).
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Section 2: Gas, oil and biomass-fired boilers
account in the values used for the calculation of the boiler seasonal efficiency using Equations 2 or 3.1, or
the three-step method and Equations 3.2 and 3.3, as appropriate.
Condensing boiler means a boiler that offers a higher energy efficiency by recovering heat from the flue
gases. This is achieved by increasing the heat exchanger surface area, which recovers extra sensible heat
whenever the boiler fires. The boiler becomes even more efficient when system water temperatures are
low because the larger heat exchanger area promotes condensation, allowing much of the latent heat to
be recaptured. Standing losses (when the boiler is not firing) are low, and part load performance is very
good. In multiple-boiler systems, condensing boilers can be used as the lead boiler.
Standard boiler means, in the context of this document, a non-condensing boiler.
Zone control means independent control of rooms or areas within buildings that need to be heated to
different temperatures at different times. Where several rooms or areas of a building behave in a similar
manner, they can be grouped together as a ‘zone’ and put on the same circuit and controller.
Sequence control enables two or more heating boilers to be switched on or off in sequence when the
heating load changes. This maximises the efficiency of the boilers, so reducing fuel consumption, and
reduces wear and tear on the boilers.
Direct acting weather compensation is a type of control that enables a heat generator to work at its
optimum efficiency. The control allows the boiler to vary its operating flow temperature to suit the
external temperature conditions and the temperatures inside the building. Weather compensation
relies on communication between an external sensor and one inside the boiler. The boiler’s water flow
temperature is varied accordingly, so that energy is not wasted by the boiler turning on and off.
Weather compensation via a mixing valve is similar to direct acting weather compensation, except that
the outside temperature is used to control the temperature of water supplied to the heat emitters by
mixing the boiler flow and return rather than by altering the boiler temperature.
Optimum start is a control system or algorithm which starts plant operation at the latest time possible
to achieve specified conditions at the start of the occupancy period.
Optimiser is a control system employing an optimum start algorithm.
Optimum stop is a control system or algorithm which stops plant operation at the earliest possible time
such that internal conditions will not deteriorate beyond preset limits by the end of the occupancy period.
Two-stage burner control is a type of control that offers two distinct boiler firing rates.
Multi-stage burner control is a type of control that offers more than two distinct firing rates, but without
continuous adjustment between firing rates.
Modulating burner control is a type of control that provides a continuously variable firing rate, which is
altered to match the boiler load over the whole turndown ratio.
Decentralisation means the replacement of centralised boiler plant and its associated distribution
pipework with several smaller, more accurately sized boiler plants, installed within or adjacent to the
buildings or systems they serve. This eliminates long pipe runs between buildings or through unheated
areas, so reducing heat losses.
Building management system (BMS) means a building-wide network which allows communication with
and control of items of HVAC plant (and other building systems) from a single control centre, which may
be local or remote. More advanced (‘full’) building management systems offer a wide range of functions,
including sequential control, zone control, weather compensation, frost protection and night set-back, as
well as monitoring and targeting.
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2.4Determining boiler seasonal efficiency
Single-boiler systems and multiple-boiler systems with identical boilers
For boilers the relevant heat generator seasonal efficiency is the boiler seasonal efficiency. The boiler
seasonal efficiency is a ‘weighted’ average of the efficiencies of the boiler at 15%, 30% and 100% of the
boiler output (the efficiency at 15% being taken to be the same as that at 30%). This is usually quoted by
the boiler manufacturer. Note that the efficiencies based on net calorific value should be converted to
efficiencies based on gross calorific value using the appropriate conversion factor in SAP 2012 Table E4.
The boiler efficiencies, measured at 100% load and at 30% load, are used in Equation 2 to calculate
the boiler seasonal efficiency. The weighting factors in Equation 2 reflect typical seasonal operating
conditions for a boiler.
Boiler seasonal efficiency0.8130%0.19100%
Equation 212
where:
30% is the gross boiler efficiency measured at 30% load
h100% is the gross boiler efficiency measured at 100% load.
Equation 2 applies to:
• single-boiler systems where the boiler output is  400 kW and the boiler will operate on a low
temperature system
• multiple-boiler systems where all individual boilers have identical efficiencies and where the output
of each boiler is  400 kW operating on low temperature systems.
For boilers with an output  400 kW, the manufacturer’s declared efficiencies should be used.
Multiple-boiler systems with non-identical boilers replacing existing systems
Where more than one boiler is installed on the same heating system and the efficiencies of the boilers
are not all identical, Equation 3.1 should be used to calculate the overall boiler seasonal efficiency. All
boilers should be included in the calculation, even when some are identical.
The boiler seasonal efficiency for multiple-boiler systems with non-identical boilers is:
S(hBSE  R)
hOBSE
=
SR
Equation 3.1
where:
h
is the gross overall boiler seasonal efficiency, being an average weighted by boiler output of the
OBSE
individual seasonal boiler efficiencies
hBSE is the gross boiler seasonal efficiency of each individual boiler calculated using Equation 2
R is the rated output in kW of each individual boiler (at 80/60°C).
12
16
This equation assumes that the efficiency at 15% load is the same as at 30% load (and the equation has been simplified accordingly).
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Section 2: Gas, oil and biomass-fired boilers
Multiple-boiler systems in new buildings
In the case of multiple boilers in new buildings, the more accurate three-step method described
below should be used to calculate the overall seasonal boiler efficiency. These steps can readily be
programmed into a spreadsheet to automate the calculation.
Step 1
Determine the load on each boiler for each of the three system part-load conditions of 15%, 30% and 100%.
For example, if the total system output is made up of three equally sized boilers, at 15% of system output
the lead boiler will be operating at 45% of its rated output, with the other two boilers switched off.
Step 2
Determine the efficiency of each boiler for the above operating conditions. In the above example,
the efficiency of the boiler operating at 45% can be determined by linear interpolation between its
efficiencies at 30% and 100% of rated output. Where it is necessary to determine the efficiency of an
individual boiler at 15% of rated output, this should be taken as the same as the efficiency at 30% of
rated output. (Note that the efficiency at 15% of rated output will only be needed if a single boiler meets the full design output.)
Step 3
Calculate the overall operating efficiency at each of the system part load conditions using:
hpQp/S(qb,p/hb,p)
Equation 3.2
where:
hp is the system efficiency at part load condition p, i.e. 15%, 30% and 100% of system rated output
Qp is the system heat output at part load condition p
qb,p is the individual boiler heat output at system part load condition p
hb,p is the individual boiler efficiency at system part load condition p.
Calculate the overall boiler seasonal efficiency as the weighted average of the efficiencies at the three
load conditions using:
hOBSE0.36h15%0.45h30%0.19h100%
Equation 3.3
Table 2 is a worksheet for following through these calculations (using manufacturer data for boiler
efficiency at 100% and 30% output). Table 3 shows a completed example calculation using this
worksheet, for the case where a system with a rated output of 625 kW is served by three boilers, each
rated at 250 kW. The first two boilers are condensing boilers, while the third is a standard boiler. Because
the installation is oversized (750 kW compared to 625 kW), at full system output the final boiler is only
operating at 50% output (125/250).
The notes at the foot of the table illustrate how the various values are calculated.
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Table 2 Worksheet for calculating the overall boiler seasonal efficiency of a multiple-boiler
system using the alternative three-step method
Boiler no
Rating kW
Boiler % efficiency
at boiler outputs of
Boiler % output at
system outputs of
100%
15%
30%
30%
Boiler % efficiency at
system outputs of
100%
15%
30%
100%
0.36
0.45
0.19
1
2
3
System efficiency at part load
Weighting factor
Overall heat generator seasonal efficiency
Table 3 Example calculation of the overall boiler seasonal efficiency of a multiple-boiler system
in a new building
Boiler % efficiency at
boiler outputs of
Boiler % output at
system outputs of
Boiler % efficiency at
system outputs of
Boiler no
Rating kW
30%
100%
15%
30%
100%
15%
30%
100%
1
250
90%
86%
38.0%
75.0%
100.0%
89.6%[1]
87.4%
86.0%
2
250
90%
86%
not firing
not firing
100.0%
not firing
not firing
86.0%
3
250
85%
82%
not firing
not firing
50.0%
not firing
not firing
84.1%
89.6%
87.4%
85.6%[2]
0.36
0.45
0.19
System efficiency at part load
Weighting factor
Overall heat generator seasonal efficiency
Notes
[1] Calculated by linear interpolation hb,ph30% – (h30% – h100%) 
h1,15%h30% – (h30% – h100%) 
87.9%[3]
(qb,p – 30%)
(100% – 30%)
(38% – 30%)
(100% – 30%)
[2] Calculated by dividing the thermal output of the system (625 kW) by the rate of fuel consumption,
which is given by the sum of the boiler outputs divided by their individual operating efficiency, i.e.
h100%
625
250100%
86.0%

250100%
86.0%

25050% = 85.6%
84.1%
[3] Calculated as the weighted average, i.e.
89.6%0.3687.4%0.4585.6%0.1987.9%
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Section 2: Gas, oil and biomass-fired boilers
2.5 Boilers in new buildings
Background
New buildings should be provided with high efficiency condensing or non-condensing boilers that meet
the recommended minimum standards for heat generator seasonal efficiency in this guide.
Commercial heating systems are inherently more complicated than domestic systems with a wider
range of temperatures and heat emitters. The selection of condensing or non-condensing boilers will be
determined by application and physical constraints.
Note: Water quality can have a major impact on system efficiency. It is important that designers take
appropriate measures to ensure that the system water is of good quality.
Condensing boilers will meet projected efficiencies only when they operate with a system return
temperature between 30°C and 40°C for 80% of the annual operating hours. With a return temperature
of 55°C and above, condensing boilers will not produce condensate and will have similar efficiencies to
non-condensing high efficiency boilers. Some systems are suitable for weather compensation, which
allows return temperatures to fall into the condensing range for some periods of the heating season, and
they may be best served by a mixture of condensing and non-condensing boilers.
The efficiency value that should be entered into accredited NCM tools to calculate the carbon dioxide
emission rate is the effective heat generator seasonal efficiency. For boilers in new buildings, no heating
efficiency credits can be gained and the effective heat generator seasonal efficiency is therefore the
same as the heat generator seasonal efficiency.
Recommended minimum standards
To meet relevant energy efficiency requirements in the Building Regulations when installing boiler plant
in new buildings:
a. where a single boiler is used to meet the heat demand, its boiler seasonal efficiency (gross calorific
value) calculated using Equation 2 should be not less than the value in Table 4
b. for multiple-boiler systems, the boiler seasonal efficiency of each boiler should be not less than 82%
(gross calorific value), as calculated using Equation 2; and the overall boiler seasonal efficiency of the
multiple-boiler system, as defined by the three-step method and calculated using Equations 3.2 and
3.3, should be not less than the value in Table 4
c. the relevant minimum controls package in Table 5 should be adopted.
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Table 4 Recommended minimum heat generator seasonal efficiency for boiler systems
in new buildings
Fuel type
System
Boiler seasonal efficiency
(gross calorific value)
Natural gas
Single-boiler  2 MW output
91%
Single-boiler  2 MW output
86%
Multiple-boiler
82% for any individual boiler
86% for overall multi-boiler system
Single-boiler  2 MW output
93%
Single-boiler  2 MW output
87%
Multiple-boiler
82% for any individual boiler
87% for overall multi-boiler system
Single-boiler
84%
Multiple-boiler
82% for any individual boiler
84% for overall multi-boiler system
LPG
Oil
Table 5 Recommended minimum controls package for new boilers and multiple-boiler systems
Boiler plant output
Package
Minimum controls
 100 kW
A
a. Timing and temperature demand control, which should be zone specific
where the building floor area is greater than 150 m2.
b. Weather compensation except where a constant temperature supply
is required.
100 kW to 500 kW
B
a. Controls package A above.
b. Optimum start/stop control with either night set-back or frost
protection outside occupied periods.
c. Two-stage high/low firing facility in boiler, or multiple boilers with
sequence control to provide efficient part-load performance.
Note: The heat loss from non-firing boiler modules should be limited by
design or application. For boilers that do not have low standing losses, it may
be necessary to install isolation valves or dampers.
 500 kW individual boilers
C
a. Controls package A and controls package B.
b. For gas-fired boilers and multi-stage oil-fired boilers, fully modulating
burner controls.
2.6Boilers in existing buildings
Background
Boiler efficiencies have improved markedly over recent years. A modern boiler meeting the minimum
requirements of the Boiler Efficiency Directive has a boiler seasonal efficiency of approximately 78.5%
(based on gross calorific value).
This guidance recognises that in many cases using condensing boiler technology in existing buildings
would be either technically impractical (due to flueing constraints) or economically unviable. For this
reason non-condensing boilers may be used provided that they meet the recommended minimum
efficiency standards given in this section.
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Section 2: Gas, oil and biomass-fired boilers
Replacement boilers
To meet relevant energy efficiency requirements in the Building Regulations when installing boiler plant
in existing buildings:
a. the boiler seasonal efficiency of each boiler (in a single-boiler system or a multiple-boiler system
with identical boilers) calculated using Equation 2 should be not less than the value in Table 6
b. f or multiple-boiler systems using non-identical boilers, the overall boiler seasonal efficiency
calculated using Equation 3.1 should be not less than the value in Table 6
c. the controls package in Table 7 should be adopted – i.e. zone control, demand control and time control
d. the effective boiler seasonal efficiency should be not less than the value in Table 6. To meet the
standard, it may be necessary to adopt additional measures from Table 8 in order to gain heating
efficiency credits (see below).
Table 6 Recommended minimum heat generator seasonal efficiency for boiler systems in
existing buildings
Fuel type
Effective boiler seasonal efficiency
(gross calorific value)
Boiler seasonal efficiency
(gross calorific value)
Natural gas
84%
82%
LPG
85%
83%
Oil
86%
84%
Table 7 Recommended minimum controls package for replacement boilers in existing buildings
Minimum controls package
Suitable controls
a. Zone control
Zone control is required only for buildings where the floor area is greater
than 150 m2. As a minimum, on/off control (e.g. through an isolation valve for
unoccupied zones) should be provided.
b. Demand control
Room thermostat which controls through a diverter valve with constant
boiler flow water temperature. This method of control is not suitable for
condensing boilers.
c. Time control
Time clock controls.
2.7 Heating efficiency credits for replacement boilers
Where the boiler seasonal efficiency is less than the minimum effective boiler seasonal efficiency for
that type of boiler, additional measures will need to be adopted to achieve the minimum effective heat
generator seasonal efficiency in Table 6.
Table 8 indicates the measures that may be adopted and the relevant heating efficiency credits that
are applicable. It should be noted that the maximum number of heating efficiency credits that can be
claimed is 4 percentage points.
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Table 8 Heating efficiency credits for measures applicable to boiler replacement in
existing buildings
Heating efficiency
credits
(% points)13
Measure
Comments
A
Boiler oversize  20%
2
Boiler oversize is defined as the amount by
which the maximum boiler heat output exceeds
the system heat output at design conditions,
expressed as a percentage of that system heat
output. For multiple-boiler systems the maximum
boiler heat output is the sum of the maximum
outputs of all the boilers in the system.
B
Multiple boilers
1
Where more than one boiler is used to meet the
heat load.
C
Sequential control of multipleboiler systems
1
Applies only to multiple-boiler/module
arrangements. It is recommended that the
most efficient boiler should act as the lead in a
multiple-boiler system.
D
Monitoring and targeting
1
Means of identifying changes in operation or
onset of faults. The credit can only be claimed
if metering is included and a scheme for
data collection is provided and available for
inspection.
E
i. Thermostatic radiator valves (TRVs)
alone. Would also apply to fanned
convector systems
1
TRVs enable the building temperature to be
controlled and therefore reduce waste of energy.
ii. Weather (inside/outside
temperature) compensation system
using a mixing valve
1.5
Provides more accurate prediction of load and
hence control.
iii. Addition of TRV or temperature
zone control to ii above to ensure
full building temperature control
1
This credit is additional to Eii above.
i. A ‘room’ thermostat or sensor that
controls boiler water temperature in
relation to heat load
0.5
ii. Weather (inside/outside
temperature) compensation system
that is direct acting
2
Provides more accurate prediction of load and
hence control.
iii. Addition of TRV or temperature
zone control to i or ii above to
ensure full building temperature
control
1
This credit is additional to Fi or Fii above. Note Fi
and Fii are not used together.
F
13
22
The maximum that can be claimed is 4 points.
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Section 2: Gas, oil and biomass-fired boilers
Table 8 Heating efficiency credits for measures applicable to boiler replacement in
existing buildings (continued)
Heating efficiency
credits
(% points)13
Measure
G
Comments
i. Optimum start
1.5
A control system which starts plant operation
at the latest time possible to achieve specified
conditions at the start of the occupancy period.
ii. Optimum stop
0.5
A control system which stops plant operation
at the earliest possible time such that internal
conditions will not deteriorate beyond preset
limits by the end of the occupancy period.
iii. Optimum start/stop
2
A control system which starts plant operation
at the latest time possible to achieve specified
conditions at the start of the occupancy period
and stops plant operation at the earliest possible
time such that internal conditions will not
deteriorate beyond preset limits by the end of
the occupancy period.
Note that if optimum start/stop systems are
installed, credits Gi and Gii cannot also be
claimed.
H
Full zoned time control
1
Allowing each zone to operate independently in
terms of start/stop time. Only applicable where
operational conditions change in different zones.
Does not include local temperature control.
I
Full building management system
(BMS)
4
A full BMS linked to the heating plant will
provide: sequential control of multiple
boilers, full zoned time control and weather
compensation where applicable; frost protection
or night set-back; optimisation and monitoring
and targeting.
Note that if a full BMS is installed, no further
heating efficiency credits can be claimed.
J
Decentralised heating system
1
Elimination of long pipe runs between buildings
or through unheated areas in buildings in order to
reduce excessive heat losses.
Example: Using heating efficiency credits to achieve the minimum effective heat generator seasonal
efficiency for a boiler system in an existing building
An existing boiler is to be replaced with a gas boiler with a boiler seasonal efficiency of 82%, the
minimum allowed by Table 6.
The boiler’s effective boiler seasonal efficiency needs to be at least 84% according to Table 6, which
means that 2 percentage points of heating efficiency credits are needed.
The following approach would achieve this:
a. restrict boiler oversizing to 15% (after a detailed assessment of load)
b. fit a room thermostat to control boiler water temperature in relation to heat load
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c. use two equally sized boilers to meet the heat load in place of the existing single boiler
d. fit TRVs to control the temperature in areas other than where the room thermostat is fitted.
Table 9 below shows how credits would be awarded in this example.
Table 9 Example to illustrate allocation of heating efficiency credits for a replacement boiler in
an existing building
Plant description
Heating efficiency credits
(% points)
Boiler oversizing is less than 20%
2
System controlled by room thermostat which controls boiler water temperature
0.5
System uses TRVs to ensure full building temperature control
1
Multiple boilers
1
Total credits
4.5
Effective boiler seasonal efficiency
= boiler seasonal efficiencymaximum of 4 heating efficiency credits
= 82486%
In this example the minimum effective boiler seasonal efficiency of 84% is exceeded by 2 percentage points.
2.8Biomass boilers
Background
The method in Section 2.4 for calculating the seasonal efficiency of single and multiple boilers fired by gas, LPG and oil is not appropriate for biomass boilers.
For biomass boilers, requirements and test methods are covered by BS EN 12809:2001+A1:2004 Residential
independent boilers fired by solid fuel. Nominal heat output up to 50 kW. Requirements and test methods.
Recommended minimum standards
To meet relevant energy efficiency requirements in the Building Regulations:
a. the efficiency of biomass boilers at their nominal load should be at least:
i. 65% for independent gravity-fed boilers  20.5 kW
ii. 75% for independent automatic pellet/woodchip boilers
b. controls as for gas, LPG and oil boilers in Table 5 should be provided, where technically feasible.
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Section 3: Heat pumps
Section 3:Heat pumps
3.1 Introduction
This section gives guidance on specifying heat pumps to provide space heating and domestic hot water
in new and existing buildings to meet relevant energy efficiency requirements in the Building Regulations.
The heat pumps covered in this section take heat energy from a low temperature source and upgrade it
to a higher temperature at which it can be usefully employed for heating.
The guidance covers measures, such as additional controls, that can be used to gain heating efficiency
credits to improve the coefficient of performance of heat pumps.
For guidance on reverse cycle heat pumps that also provide cooling, see Section 9 of this guide.
3.2 Scope of guidance
The guidance in this section applies to the commercial heat pump systems identified in Table 10, which
categorises the different types of heat pump according to:
• the source of the heat
• the medium by which it is delivered, and
• the technology.
Table 10 Heat pump types and associated test standards
Heat pump type
Technology
Sub-technology
Test standard
Electrically-driven
warm air
Ground-
to-air
Single packagevariable refrigerant flow warm air systems
ISO 13256-114
Energy transfer systems (matching heating/cooling demands in buildings)
Water-
to-air
Single packagevariable refrigerant flow warm air systems
Air-to-air
Single package
BS EN 14511-315
Energy transfer systems (matching heating/cooling demands in buildings)
BS EN 14511-3
Split system
Multi-split system
Variable refrigerant flow systems
Electrically-driven
warm water
Gas-enginedriven
14
15
16
Ground-
to-water
Single packagevariable refrigerant flow warm air systems
Water-
to-water
Single packagevariable refrigerant flow warm air systems
Air-towater
Single package
ISO 13256-216
Split package
BS EN 14511-3
Split package
BS EN 14511-3
Split packagevariable refrigerant flow warm air systems
Available as variable refrigerant flow warm air systems
Generally to
BS EN 14511-3
ISO 13256-1 Water-source heat pumps. Testing and rating for performance. Part 1: Water-to-air and brine-to-air heat pumps.
BS EN 14511-3:2013 Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors for space heating and cooling. Test methods.
ISO 13256-2 Water-source heat pumps. Testing and rating for performance. Part 2: Water-to-water and brine-to-water heat pumps.
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3.3 Key terms
Coefficient of performance (COP) is a measure of the efficiency of a heat pump at specified source and
sink temperatures, but may not accurately represent installed performance:
Heating COPheat output / power input Equation 4
% COP (COP100) is the heat generator efficiency.
Effective % COP is the % COP with heating efficiency credits.
The COP of a heat pump should be determined in accordance with the appropriate test standard identified
in Table 10. The input power items to be included in the calculation are defined in the standard.
Seasonal coefficient of performance (SCOP) is the overall coefficient of performance of the unit for the
designated heating season. It makes general assumptions about the amount of auxiliary heating needed
to top up the space and water heating available from the heat pump.
SCOP is measured in accordance with the procedures in BS EN 14825:2013 Air conditioners, liquid chilling
packages and heat pumps with electrically driven compressors for space heating and cooling. Testing and
rating at part load conditions and calculation of seasonal performance.
The National Calculation Methodology for calculating carbon dioxide emission rates from buildings uses SCOP.
Seasonal performance factor (SPF) is another measure of the operating performance of an electric heat
pump over the season. It is the ratio of the heat delivered to the total electrical energy supplied over
the season, but there are up to seven different ways to draw the system boundaries. For example, SPFH2
excludes auxiliary resistance heating while SPFH4 includes it – making a large difference.
SAP 2012 calculations (for dwellings) use SPF – either measured values for products listed in the Product
Characteristics Database, or the default values in Table 4a for products not listed there.
The Microgeneration Certification Scheme installation standard, MIS 3005, uses SPF to calculate system
performance (although the heat pump product standard, MCS 007, currently specifies a minimum COP).
Seasonal primary energy efficiency ratio (SPEER) is an emerging rating figure reflecting the use of primary
energy for all types of heat pump, fossil fuel boiler and gas-driven cogeneration technologies, as well as
hybrid systems where solar heating or a heat pump is backed up with electric heating or a fossil fuel boiler.
Energy labelling with the SPEER will be mandatory from 2015 under the Energy Labelling Directive. Testing
and rating will be in accordance with BS EN 14825, as for SCOP.
3.4 Heat pumps in new and existing buildings
At the time of preparation of this guide, European Commission Regulation No 206/2012 sets standards
only for the SCOP of electrically-driven air-to-air heat pumps with an output  12 kW. There are
currently no European test standards for part-load testing of air-to-air heat pumps with an output
 12 kW or for other types of heat pump17, and so the performance of these must be specified using COP
obtained at the heating system rating conditions.
17
26
Requirements for heat pumps delivering water with an output up to 400 kW are expected to come into force in August 2015.
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Section 3: Heat pumps
The current recommendations in this guide are that heat pumps in new and existing buildings should:
a. if air-to-air with an output  12 kW, have at least a SCOP ‘D’ rating for the median temperature range
in BS EN 14825
b. or else have a COP which is not less than the value in Table 11
c. feature as a minimum the controls package in Table 12.
Table 11 Recommended minimum COP for heat pumps in new and existing buildings
Heat pump type
Minimum COP at the rating conditions18
All types (except air-to-air with output  12 kW, absorption
and gas-engine) for space heating
2.5
All types (except absorption and gas-engine) for domestic
hot water heating
2.0
Absorption
0.5
Gas-engine
1.0
For non-residential buildings, the heat pump system can be sized to meet either the full heating and hot
water demand or part of it. Economically viable installations provide at least 50% of the heating and hot
water demand for the building.
Table 12 Recommended minimum controls package for heat pump systems in new and
existing buildings
Heat source/sink
Technology
Minimum controls package
All types
All
technologies
A
Single package
B
Air-to-air
Split system
Multi-split
system
Variable
refrigerant flow
system
18
a. On/off zone control. If the unit serves a single zone, and for buildings
with a floor area of 150 m2 or less, the minimum requirement is achieved
by default.
b. Time control.
a. Controls package A above.
b. Heat pump unit controls for:
i. control of room air temperature (if not provided externally)
ii. control of outdoor fan operation
iii. defrost control of external airside heat exchanger
iv. control for secondary heating (if fitted).
c. External room thermostat (if not provided in the heat pump unit) to
regulate the space temperature and interlocked with the heat pump
unit operation.
Rating conditions are standardised conditions for determining performance specified in BS EN 14511:2013 Air conditioners, liquid chilling packages and heat pumps with electrically
driven compressors for space heating and cooling.
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Table 12 Recommended minimum controls package for heat pump systems in new and
existing buildings (continued)
Heat source/sink
Technology
Minimum controls package
Water-to-air
Ground-to-air
Single package
energy transfer
systems
(matching
heating/
cooling
demand in
buildings)
D
a. Controls package A above.
b. Heat pump unit controls for:
i. control of room air temperature (if not provided externally)
ii. control of outdoor fan operation for cooling tower or dry cooler
(energy transfer systems)
iii. control for secondary heating (if fitted) on air-to-air systems
iv. control of external water pump operation.
c. External room thermostat (if not provided in the heat pump unit) to
regulate the space temperature and interlocked with the heat pump
unit operation.
Air-to-water
Water-to-water
Ground-to-water
Single package
E
Split package
a. Controls package A above.
b. Heat pump unit controls for:
i. control of water pump operation (internal and external as appropriate)
ii. control of water temperature for the distribution system
iii. control of outdoor fan operation for air-to-water units
iv. defrost control of external airside heat exchanger for air-to-water systems.
c. External room thermostat (if not provided in the heat pump unit) to
regulate the space temperature and interlocked with the heat pump
unit operation.
Gas-engine-driven
heat pumps are
currently available
only as variable
refrigerant flow
warm air systems
Multi-split
F
Variable
refrigerant flow
a. Controls package A above.
b. Heat pump unit controls for:
i. control of room air temperature (if not provided externally)
ii. control of outdoor fan operation
iii. defrost control of external airside heat exchanger
iv. control for secondary heating (if fitted).
c. External room thermostat (if not provided in the heat pump unit) to
regulate the space temperature and interlocked with the heat pump
unit operation.
3.5 Heating efficiency credits for heat pump systems in existing buildings
Heating efficiency credits can be gained for heat pump systems installed in existing buildings by adopting
the additional measures in Table 13. These credits are added to the % COP to produce the effective % COP.
Table 13 Heating efficiency credits for additional measures applicable to heat pump systems in
existing buildings
Measure
Heating efficiency
credits (% points)
 20% oversizing
2
The amount by which the maximum heat pump output exceeds the
system heat output at design conditions, expressed as a percentage of
that system heat output.
Optimum stop
2
A control system which stops plant operation at the earliest possible
time such that internal conditions will not deteriorate beyond preset
limits by the end of the occupancy period.
Full zone control
2
Allows each zone to operate independently in terms of start/stop time.
Only appropriate where operational conditions change in different zones.
Monitoring and targeting
2
Means of identifying changes in operation or onset of faults.
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Section 3: Heat pumps
Example: Using heating efficiency credits to achieve the recommended standard for effective % COP for
a heat pump installation
A proposed system has an air-to-water, electrically-driven heat pump supplying heat to an underfloor
heating system. The COP of the heat pump tested to BS EN 14511 is 2.46, which is below the minimum
standard recommended by Table 11 for space heating.
The minimum controls package recommended by Table 12 is package E, comprising:
a. zone control and time control
b. heat pump unit controls for:
i. control of outdoor fan operation for cooling tower or dry cooler (energy transfer systems)
ii. control of external water pump operation and water temperature for the distribution system
c. room thermostat to regulate the space temperature and interlocked with the heat pump unit
operation.
Table 14 shows the heating efficiency credits that can be gained by adding optimum stop control and full
zone control.
Effective % COP% COPheating efficiency credits2464250%
The effective COP is therefore 2.50, which meets the minimum required by Table 11.
Table 14 Example to illustrate the allocation of heating efficiency credits to a new heat pump
system in an existing building
Measure
Heating efficiency credits (% points)
Measures specified in controls package A
0 (as this is the minimum standard)
Measures specified in controls package E
0 (as this is the minimum standard)
Optimum stop
2
Full zone control
2
Total credits
4
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3.6 Supplementary information
Heat source/sink
Technology
Comments
Air-to-air
Single package
Units may be ducted on one or other of the supply and return air sides or
ducted on both sides. Ducting needs to be designed to take into account the
maximum specific fan power allowable (see Section 10 of this guide) and to
maintain the minimum allowable coefficient of performance.
Split
A split system will comprise a single outdoor unit and a single indoor unit as a
package. Multi-split and variable refrigerant flow systems will comprise a single
outdoor unit and two or more indoor units as a package. Several packages may
be used to satisfy the requirements of the building.
Multi-split
Variable
refrigerant flow
Gas-engine-driven
Water-to-air
Single package
Ground-to-air
Energy transfer
Air-to-water
Single package
Water-to-ground
Split package
Water-to-water
In order for efficiencies to be maintained, all connecting pipework should
be installed in accordance with manufacturers’ recommendations (diameter,
length, insulation and riser height). Any ducting should be designed to take
into account the maximum specific fan power allowable and to maintain the
minimum allowable coefficient of performance.
Energy transfer systems generally consist of multiple water-source heat pumps
connected in parallel to a common closed water loop. They are installed to
offset the simultaneous heating and cooling demand in a building due to the
different loads present on the aspects of the building. Water circulation pumps
for the closed loop should be taken into consideration along with the fan
power required for the cooling tower or dry cooler or energy for water pumps
for the ground loop if this method is utilised for heat injection and rejection.
Any ducting should be designed to take into account the maximum specific
fan power allowable and to maintain the minimum allowable coefficient of
performance.
Water circulation pumps for the delivery of heated water to the building along
with the energy of water pumps used for the heat source (water or ground)
should be considered in the calculation. Any ducting should be designed to
take into account the maximum specific fan power allowable and to maintain
the minimum allowable coefficient of performance.
Additional guidance on design criteria for heating systems with integrated heat pumps is given in BS EN 15450:2007 Heating
systems in buildings. Design of heat pump heating systems.
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Section 4: Gas and oil-fired warm air heaters
Section 4:Gas and oil-fired warm air heaters
4.1 Introduction
This section gives guidance on specifying gas and oil-fired warm air heaters for space heating in new and
existing buildings to meet relevant energy efficiency requirements in the Building Regulations. It includes
guidance on measures, such as additional controls, that can be used to gain heating efficiency credits to
improve the heat generator seasonal efficiency.
4.2Scope of guidance
The guidance in this section covers the warm air heaters listed in Table 15. The guidance also covers
indirect gas or oil-fired heat exchangers (as used in large ducted systems for office blocks, shopping and
leisure complexes, etc.) to provide heating and fresh or conditioned air. Warm air central heating systems
are not within the scope of this section but are covered in the relevant heat generator section and
Section 10 Air distribution.
Table 15 Warm air heaters and test methods
Type of warm air heater
Product standard
Type 1
Gas-fired forced convection without a fan to assist transportation of
combustion air and/or combustion products
BS EN 621:200919
Type 2
Gas-fired forced convection incorporating a fan to assist transportation of
combustion air and/or combustion products
BS EN 1020:200920
Type 3
Direct gas-fired forced convection
BS EN 525:200921
Type 4
Oil-fired forced convection
BS EN 13842:200422
4.3 Key terms
Heat generator seasonal efficiency of air heaters, since they operate under the same conditions at all
times, is equivalent to their measured steady state thermal efficiency (net calorific value), which can be
obtained from the heater manufacturer’s data and converted to efficiency (gross calorific value) using the
conversion factors in SAP 2012 Table E4.
For indirect-fired heaters, data values for heat output and net heat input are measured using the
efficiency test methods described in BS EN 1020, BS EN 621 or BS EN 13842 as appropriate.
For direct-fired heaters, the efficiency should be calculated using the method described in BS EN 525.
19202122
19
BS EN 621:2009 Non-domestic gas-fired forced convection air heaters for space heating not exceeding a net heat input of 300 kW, without a fan to assist transportation of combustion
air and/or combustion products.
20 BS EN 1020:2009 Non-domestic forced convection gas-fired air heaters for space heating not exceeding a net heat input of 300 kW, incorporating a fan to assist transportation of
combustion air or combustion products.
21 BS EN 525:2009 Non-domestic direct gas-fired forced convection air heaters for space heating not exceeding a net heat input of 300 kW.
22 BS EN 13842:2004 Oil-fired convection air heaters. Stationary and transportable for space heating.
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The calculation of the thermal efficiency (net) should:
• take account of the heater and the exhaust chimney within the building envelope
• exclude fans.
Effective heat generator seasonal efficiency is the heat generator seasonal efficiency with added heating
efficiency credits (see below). It is the value entered into NCM tools such as SBEM to calculate the
building carbon dioxide emission rate (BER).
4.4Warm air heaters in new and existing buildings
Warm air systems in new and existing buildings should have:
a. an effective heat generator seasonal efficiency which is no worse than in Table 16
b. a controls package featuring, as a minimum, time control, space temperature control and, where
appropriate for buildings with a floor area greater than 150 m2, zone control.
Table 16 Recommended minimum effective heat generator seasonal efficiency
Warm air heater type (see Table 15)
Effective heat generator seasonal efficiency
(net calorific value)
Types 1, 2 natural gas
91%
Types 1, 2 LPG
91%
Type 3*
100%
Type 4
91%
* For Type 3 air heaters, 100% of the net heat input is delivered to the space. Specific ventilation requirements as defined in
BS EN 525 should be met.
4.5 Heating efficiency credits for warm air heaters in new and existing buildings
Heating efficiency credits can be gained by adopting the additional measures listed in Table 17.
Table 17 Heating efficiency credits for additional measures applicable to warm air heaters
Measure
Heating efficiency
credits
(% points)
Optimum stop
1
A control system which stops plant operation at the earliest
possible time such that internal conditions will not deteriorate
beyond preset limits by the end of the occupancy period.
Hi/Lo burners
2
Two-stage burners which enable two distinct firing rates.
Modulating burners
3
Burner controls which allow continuous adjustment of the firing rate.
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Section 4: Gas and oil-fired warm air heaters
Destratification fans and air-induction schemes
It is recognised that destratification fans and air-induction schemes may improve the efficiency of a
warm air system and significantly reduce the carbon emissions associated with the heating system. The
benefits of these measures are already taken into account by the NCM so no heating efficiency credits
can be gained by using them. Note that warm air systems with air induction schemes or destratification
fans should not be confused with central heating systems that have air distribution.
Example: Using heating efficiency credits to exceed the minimum effective heat generator seasonal
efficiency for a warm air heater
A proposed building has a gas-fired forced-convection warm air heater without a fan to assist
transportation of combustion air or combustion products. When tested to BS EN 621:2009 the thermal
efficiency (net calorific value) is found to be 91%, which meets the minimum effective heat generating
efficiency recommended for this type of system in Table 16.
The minimum controls package specified in paragraph 4.4b comprises zone, space temperature and time
controls. Table 18 shows how credits are awarded by adding optimum stop control, modulating burners
and destratification fans.
Table 18 Example to illustrate the allocation of heating efficiency credits to a warm air
heater system
Measure
Heating efficiency credits (% points)
Zone, space and temperature controls
0 (as this is the minimum standard)
Modulating burners
3
Optimum stop
1
Destratification fans
0 (as the benefits are already recognised by the NCM)
Total credits
4
Effective heat generator seasonal efficiencynet thermal efficiencyheating efficiency credits
91495%
The effective heat generator seasonal efficiency is therefore 95%, exceeding the minimum standard by
4 percentage points. The value that should be entered into the accredited NCM tool to calculate the
carbon dioxide emission rate is 95%.
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Section 5:Gas and oil-fired radiant heaters
5.1 Introduction
This section gives guidance on specifying radiant heaters for space heating in new and existing buildings
to meet relevant energy efficiency requirements in the Building Regulations. It includes guidance on
measures, such as additional controls, that can be used to gain heating efficiency credits to improve the
heat generator seasonal efficiency.
5.2 Scope of guidance
The guidance in this section covers the types of radiant heater listed in Table 19.
Table 19 Types of radiant heater and associated product standards
Radiant heater type
Product standard
Luminous radiant heater
BS EN 419-1:200923
Non-luminous radiant heater
BS EN 416-1:200924
Multi-burner radiant heater
BS EN 777 series25
Oil-fired radiant heater
N/A
5.3 Key terms
Radiant heater seasonal efficiency (heat generator seasonal efficiency) is equivalent to thermal efficiency
(net calorific value).232425
For flued appliances, the manufacturer of the radiant heater should declare a thermal efficiency
measured to the test standards BS EN 102026 or BS EN 1384227 as applicable.
The calculation of the thermal efficiency (net calorific value) should:
a. take account of the radiant heater and associated flue pipe/tailpipe within the building envelope
b. exclude fans.
23
24
25
BS EN 419-1:2009 Non-domestic gas-fired overhead luminous radiant heaters. Safety.
BS EN 416-1:2009 Single-burner gas-fired overhead radiant tube heaters. Safety.
BS EN 777-1:2009 Multi-burner gas-fired overhead radiant tube heater systems for non-domestic use. System D. Safety.
BS EN 777-2:2009 Multi-burner gas-fired overhead radiant tube heater systems for non-domestic use. System E. Safety.
BS EN 777-3:2009 Multi-burner gas-fired overhead radiant tube heater systems for non-domestic use. System F. Safety.
BS EN 777-4:2009 Multi-burner gas-fired overhead radiant tube heater systems for non-domestic use. System H. Safety.
26 BS EN 1020:2009 Non-domestic forced convection gas-fired air heaters for space heating not exceeding a net heat input of 300 kW, incorporating a fan to assist transportation of
combustion air or combustion products.
27 BS EN 13842:2004 Oil-fired convection air heaters. Stationary and transportable for space heating.
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Section 5: Gas and oil-fired radiant heaters
5.4 Radiant heaters
Radiant heaters in new and existing buildings should have:
a. an effective heat generator seasonal efficiency not worse than in Table 20
b. a controls package consisting of, as a minimum, time control and space temperature control with
black bulb sensors.
Table 20 Recommended minimum performance standards for radiant heaters
Effective heat generator seasonal efficiency
Appliance type
Thermal
Radiant
Luminous radiant heater – unflued
86%
55%
Non-luminous radiant heater – unflued
86%
55%
Non-luminous radiant heater – flued
86%
55%
Multi-burner radiant heater
91%
N/A
5.5 Heating efficiency credits for radiant heaters in existing buildings
Heating efficiency credits can be gained by adopting the additional measures listed in Table 21. They are
added to the heat generator seasonal efficiency (the thermal efficiency – net calorific value) to give the
effective heat generator seasonal efficiency.
Table 21 Heating efficiency credits for additional measures applicable to radiant heaters
Heating efficiency
credits (% points)
Measure
Controls
(additional to
the minimum
package)
Comments
Optimum stop
1
A control system which stops plant operation at the
earliest possible time such that internal conditions will
not deteriorate beyond preset limits by the end of the
occupancy period.
Optimum start
0.5
A control system which starts plant operation at the
latest possible time such that internal conditions will be
up to required limits at the start of the occupancy period.
Zone control
1
A control system in which each zone operates
independently in terms of start/stop time. It is only
appropriate where operational conditions change in
different zones.
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Example: Using heating efficiency credits to achieve the minimum effective heat generator seasonal
efficiency for a radiant heater system
A proposed building will have a flued non-luminous radiant heater system with a thermal efficiency (heat generator seasonal efficiency) of 84%. A black bulb sensor and an optimiser will be fitted.
The heating efficiency credits associated with these measures are added to the appliance thermal
efficiency to obtain the effective heat generator seasonal efficiency.
Table 22 shows how credits are awarded for this example.
Table 22 Example to illustrate the allocation of heating efficiency credits to a radiant
heater system
Measure
Heating efficiency credits (% points)
Black bulb sensor
0 (as minimum requirement)
Optimum stop
1
Zone control
1
Total credits
2
Effective heat generator seasonal efficiencythermal efficiencyheating efficiency credits
84286%
In this example, the application of additional measures to gain heating efficiency credits has brought the
radiant heater’s effective heat generator seasonal efficiency up to the minimum recommended value.
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Section 6: Combined heat and power and community heating
Section 6:Combined heat and power and
community heating
6.1 Introduction
This section gives guidance on specifying combined heat and power (CHP) systems for space heating, hot
water and chilled water (via absorption chillers) in new and existing buildings to meet relevant energy
efficiency requirements in the Building Regulations. Guidance on the design of community heating
systems can be found in Section 6 of the Domestic Building Services Compliance Guide.
CHP units are normally used in conjunction with boilers. The majority of the annual heat demand is
usually provided by the CHP plant, while the boilers are used to meet peak demand and in periods when
the CHP unit is not operating (for example at night or when undergoing maintenance).
CHP units may on a relatively small scale supply single buildings, or on a larger scale supply a number of
buildings through a community heating system. The most common fuel is natural gas, which can be used
in spark-ignition gas engines, micro-turbines, or gas turbines in open cycle or combined cycle.
6.2Scope of guidance
The guidance in this section covers CHP systems with a total power capacity less than 5 MWe used in
commercial applications. The CHP units may or may not supply community heating.
Guidance on community heating systems with micro-CHP (having a total power capacity less than 5 kWe)
and other heat generators is available in the Domestic Building Services Compliance Guide.
6.3 Key terms
Combined heat and power (CHP) means the simultaneous generation of heat and power in a single
process. The power output is usually electricity, but may include mechanical power. Heat outputs can
include steam, hot water or hot air for process heating, space heating or absorption cooling.
Combined Heat and Power Quality Assurance (CHPQA) is a scheme28 under which registration and
certification of CHP systems is carried out according to defined quality criteria.
CHPQA quality index is an indicator of the energy efficiency and environmental performance of a CHP
scheme relative to generation of the same amounts of heat and power by alternative means.
Power efficiency is the total annual power output divided by the total annual fuel input of a CHP unit.
28 Further information about the CHPQA programme is available at www.chpqa.com.
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6.4CHP in new and existing buildings
CHP plant in new and existing buildings should have:
a. a minimum CHPQA quality index (QI) of 105 and power efficiency greater than 20%, both under
annual operation
b. a control system that, as a minimum, ensures that the CHP unit operates as the lead heat generator
c. metering to measure hours run, electricity generated and fuel supplied to the CHP unit.
The CHP plant should be sized to supply not less than 45% of the annual total heating demand (i.e.
space heating, domestic hot water heating and process heating) unless there are overriding practical or
economic constraints.
Calculating the carbon dioxide emissions from a CHP heating system
CHP may be used as a main or supplementary heat source in community heating systems. To calculate
the carbon dioxide emission rate for a new building for the purposes of showing compliance with the
Building Regulations, the following data will need to be entered into an accredited NCM tool such as
SBEM:
a. the proportion (P %) of the annual heat demand (H MWh) to be supplied by the CHP plant (HP).
This is needed as the CHP unit is normally sized below the peak heat demand of the building and will
also be out of service for maintenance purposes
b. the overall efficiency ratio of the CHP plant (E) as defined by Equation 5 and taking account of partload operation and all heat rejection predicted by an operating model:
E(annual useful heat suppliedannual electricity generated net of parasitic electricity use)/annual energy of the fuel supplied
(in gross calorific value terms)
Equation 5
c. the heat to power ratio of the CHP plant (R), calculated for the annual operation according to
Equation 6:
Rannual useful heat supplied/annual electricity generated net of parasitic electricity use
Equation 6
The carbon dioxide emitted in kg/year for the heat supplied by a gas-fired CHP plant is then:
HP
E

HP
RE
 216 
HP
R
 519
where 216 and 519 are the assumed carbon dioxide emission factors in g/kWh for
mains gas and grid-displaced electricity respectively.
Equation 7
The carbon dioxide emitted for the balance of heat supplied by the boilers is then calculated by the
NCM tool as for a boiler only system.
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Section 6: Combined heat and power and community heating
6.5 Supplementary information
Community heating systems may include other low and zero carbon sources of energy such as
biomass heating. Emission factors should be determined based on the particular details of the scheme,
but should take account of the annual average performance of the whole system – that is, of the
distribution circuits and all the heat generating plant, including any CHP and any waste heat recovery
or heat dumping. The calculation of the building carbon dioxide emission rate should be carried out
by a suitably qualified person, who should explain how the emission factors were derived.
The design of the community heating connection and the building’s heating control system should
take account of the requirements of the community heating organisation with respect to maintaining
low return temperatures at part-load and limiting the maximum flow rate to be supplied by the
community heating system to the agreed level. A heat meter should be installed to measure the heat
energy supplied and to monitor the maximum heat demand, the maximum community heating flow
rate and the return temperatures into the community heating network.
Further guidance can be found in the following documents:
• Carbon Trust GPG 234 Community heating and CHP
• CIBSE AM12 Small-scale CHP for buildings
• HVCA TR/30 Guide to good practice – Heat pumps.
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Section 7:Direct electric space heating 7.1 Introduction
This section gives guidance on specifying direct electric heaters for space heating in new and existing
buildings. It addresses the relevant electric heater types and the minimum provision of controls.
7.2 Scope of guidance
The guidance given in this section covers the following types of electric heating systems, which may be
used to provide primary or secondary space heating:
• electric boilers
• electric warm air systems
• electric panel heaters
• electric storage systems, including integrated storage/direct systems
• electric fan heaters and fan convector heaters
• electric radiant heaters, including quartz and ceramic types.
The guidance does not cover electric heat pumps or portable electric heating devices.
7.3 Electric space heating in new and existing buildings
It is assumed that electric heating devices convert electricity to heat within a building with an efficiency
of 100%. A minimum heat generator seasonal efficiency is therefore not specified.
Electric space heating systems in new and existing buildings should meet the minimum standards for:
a. controls for electric boilers in Table 23
b. controls for electric heating systems other than boilers in Table 24.
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Section 7: Direct electric space heating
Table 23 Recommended minimum controls for electric boiler systems
Type of control
Standard
Boiler temperature
control
a. Boiler fitted with a flow temperature control and capable of
modulating the power input to the primary water depending on
space heating conditions.
Zoning
b. For buildings with a total usable floor area greater than 150 m2,
at least two space heating zones with independent time and
temperature controls using either:
i. multiple heating zone programmers, or
ii. a single multi-channel programmer.
Temperature control of
space heating
c. Separate temperature control of zones within the building using
Time control of space
and water heating
d. Provide using:
i. a full programmer with separate time control for each circuit,
Comments
either:
i. room thermostats or programmable room thermostats in all
zones, or
ii. a room thermostat or programmable room thermostat in the
main zone and individual radiator controls such as thermostatic
radiator valves (TRVs) on all radiators in the other zones, or
iii. a combination of (i) and (ii) above.
or
ii. separate timers for each circuit, or
iii. programmable room thermostats for the heating circuits, with
separate time control for all the circuits.
Note: An acceptable alternative to the above controls is any boiler management control system that
meets the specified zoning, timing and temperature requirements.
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Table 24 Recommended minimum controls for primary and secondary electric heating systems
other than electric boilers
Type of electric
heating system
Warm air
Type of control
Standard
Time and temperature
control, either integral
to the heater or
external
a. A time switch/programmer and room
Zone control
c. For buildings with a total usable floor area
Comments
thermostat, or
b. a programmable room thermostat.
greater than 150 m2, at least two space
heating circuits with independent timing and
temperature controls using either:
i. multiple heating zone programmers, or
ii. a single multi-channel programmer.
Radiant heaters
Zone or occupancy
control
a. Connection to a passive infra-red detector.
Electric radiant
heaters can provide
zone heating or be
used for a full heating
scheme. Common
electric radiant
heaters include
the quartz and
ceramic types.
Panel/skirting
heaters
Local time and
temperature control
a. Time control provided by:
i. a programmable time switch integrated into
Panel heater
systems provide
instantaneous heat.
the appliance, or
ii. a separate time switch.
b. Individual temperature control provided by:
i. integral thermostats, or
ii. separate room thermostats.
Storage heaters
a. Automatic control of input charge (based on an
Charge control
ability to detect the internal temperature and
adjust the charging of the heater accordingly).
Temperature control
b. Manual controls for adjusting the rate of heat
release from the appliance, such as adjustable
damper or some other thermostaticallycontrolled means.
Fan/fan
convector
heaters
42
Local fan control
a. A switch integrated into the appliance, or
b. a separate remote switch.
Individual temperature
control
c. Integral switches, or
d. separate remote switching.
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Section 8: Domestic hot water
Section 8:Domestic hot water 8.1 Introduction
This section gives guidance on specifying domestic hot water (DHW) systems for new and existing
buildings to meet relevant energy efficiency requirements in the Building Regulations. It includes
guidance on measures, such as additional controls, that can be used to gain heating efficiency credits to
improve the heat generator seasonal efficiency.
Note: Water quality can have a major impact on system efficiency. It is important that designers take
appropriate measures to ensure that the system water is of good quality.
As well as the Building Regulations, other regulations apply to the provision of domestic hot water.
Energy-saving measures should not compromise the safety of people or the ability of the system to
achieve approved regimes for the control of legionella.
Domestic hot water systems are referred to as hot water service systems in SBEM.
8.2Scope of guidance
The guidance in this section covers the conventional direct and indirect gas-fired, oil-fired and
electrically-heated domestic hot water systems shown in Table 25.
The recommended minimum standards set out in this section apply only to dedicated water heaters.
Central heating boilers which provide space heating and domestic hot water should meet the minimum
standards in Section 2; and heat pumps which provide domestic hot water should meet the minimum
standards in Section 3.
The guidance in this section applies to back-up gas and electric systems used with solar thermal hot
water systems, but not to solar thermal systems themselves. For solar systems with a cylinder capacity of
less than 440 litres or collector surface area less than 20 m2, consult the DCLG Domestic Building Services
Compliance Guide, or for larger systems, the CIBSE Solar heating design and installation guide.
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Table 25 Types of hot water system
Direct-fired
circulator: natural
gas and LPG
A system in which the water is supplied to the draw-off points from a hot water vessel in which
water is heated by combustion gases from a primary energy source. The unit has no storage volume
as water is stored in a supplementary storage vessel.
Direct-fired
storage: natural
gas, LPG and oil
A system in which the water is supplied to the draw-off points from an integral hot water vessel in
which water is heated by combustion gases from a primary energy source.
Direct-fired
continuous flow:
natural gas and
LPG
A system in which the water is supplied to the draw-off points from a device in which cold water
is heated by combustion gases from a primary energy source as it flows through the water heater.
The water heater is situated close to the draw-off points. The unit has no storage volume as water is
instantaneously heated as it flows through the device.
Indirect-fired
circulator: natural
gas, LPG and oil
A system in which the water is supplied to the draw-off points from a device in which water is
heated by means of an element through which the heating medium is circulated in such a manner
that it does not mix with the hot water supply. In practice the heat source is likely to be a boiler
dedicated to the supply of domestic hot water.
Instantaneous
electrically-heated
A system in which the water is supplied to the draw-off points from a device in which cold water
is heated by an electric element or elements as it flows through the water heater. The water heater
is situated close to the draw-off points. The unit has no storage volume as water is instantaneously
heated as it flows through the device.
Point-of-use
electrically-heated
A system in which the water is supplied to the draw-off points from a device in which water is
heated by an electric element or elements immersed in the stored water. The water heater is situated
close to the draw-off points and should have a storage capacity no greater than 100 litres.
Local electricallyheated
A system in which the water is supplied to the draw-off points from a device in which water is
heated by an electric element or elements immersed in the stored water. The water heater is situated
in the locality of the draw-off points and should have a storage capacity of between 100 and 300
litres. Bulk heating of the water heater should be with off-peak electricity.
Centralised
electrically-heated
A system in which the water is supplied to the draw-off points from a device in which water is
heated by an electric element or elements immersed in the stored water. The water heater is situated
centrally with a distribution system to supply water to the draw off-points and should have a
capacity greater than 300 litres. Bulk heating of the water heater should be with off-peak electricity.
8.3 Key terms
The heat generator seasonal efficiency is defined for each system type in Table 26.
The effective heat generator seasonal efficiency is the heat generator seasonal efficiency plus heating
efficiency credits gained by adopting additional measures from Table 31.
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Section 8: Domestic hot water
Table 26 Definition of heat generator seasonal efficiency for DHW systems
DHW system type
Heat generator seasonal efficiency
Comments on calculation[1]
Direct-fired
circulator: natural
gas and LPG
Equals the thermal efficiency of the heater (gross calorific value)
when tested to BS EN 15502-2-1:201229.[2]
Exclude:
a. secondary pipework
b. fans and pumps
c. diverter valves, solenoids,
actuators
d. supplementary storage
vessels.
Direct-fired
storage: natural
gas, LPG and oil
Equals the thermal efficiency of the heater (gross calorific value)
when tested using the procedures in BS EN 89:200030.[2]
Include the water heater and
insulation of the integral storage
vessel only.
Direct-fired
continuous flow:
natural gas and
LPG
Equals the thermal efficiency of the heater (gross calorific value)
when tested to BS EN 26:199831.
Exclude:
a. secondary pipework
b. fans and pumps
c. diverter valves, solenoids,
actuators
d. supplementary storage
vessels.
Indirect-fired
circulator: natural
gas, LPG and oil
Calculate using Equations 2, 3.1, or 3.2 and 3.3 (as appropriate) in
Section 2.
Include the heat generator only.
Use Equation 2 (0.8130%0.19100%) to calculate boiler seasonal
efficiency if primary return temperature  55°C.
Use boiler full load efficiency (1.0100%) at 80/60°C flow/return
temperatures if primary return temperature  55°C.
If boiler seasonal efficiency values are obtained as net values
the factors in SAP 2012 Table E4 should be used to convert to
gross values.
Electrically-heated
These are assumed 100% thermally efficient in terms of
conversion to heat within the building.
Notes
[1] For hot water systems in new buildings, standing losses are calculated in the accredited NCM tool.
[2] Where efficiency data is not readily available, efficiencies can be calculated using manufacturers’ recovery rates and
the following equations:
Gross thermal efficiencyheater output / gross input
Equation 8
Heater outputrecovery rate of heater in litres/secondspecific heat capacity of water
temperature rise of water
Equation 9
29 BS EN 15502-2-1:2012 Specific standard for type C appliances and type B2, B3 and B5 appliances of a nominal heat input not exceeding 1000 kW.
30 BS EN 89:2000 Gas fired water heaters for the production of domestic hot water. Direct-fired storage water heaters, Section 8.2, Maintenance consumption.
31 BS EN 26:1998 Gas fired instantaneous water heaters for the production of domestic hot water, fitted with atmospheric burners.
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8.4Domestic hot water systems in new and existing buildings
Domestic hot water systems in new and existing buildings should meet the recommended minimum
standards for:
a. heat losses from DHW storage vessels in Table 27, or maintenance consumption values in BS EN 89:2000
b. heat generator efficiency (gross calorific value) in Table 28
c. controls in Tables 29 and 30.
Table 27 Recommended maximum heat losses from DHW storage vessels
Nominal volume
(litres)
Heat loss
(kWh/24h)
Nominal volume
(litres)
Heat loss
(kWh/24h)
200
2.1
900
4.5
300
2.6
1000
4.7
400
3.1
1100
4.8
500
3.5
1200
4.9
600
3.8
1300
5.0
700
4.1
1500
5.1
800
4.3
2000
5.2
Notes
[1] For guidance on maximum heat losses from DHW storage vessels with a storage volume less than 200 litres, see
BS EN 15450:200732.
[2] The heat loss from electrically-heated cylinders (volume V litres) should not exceed 1.28(0.20.051V2/3) if point-of-use or 1.28(0.051V2/3) if local.
32
46
BS EN 15450:2007 Heating systems in buildings. Design of heat pump heating systems.
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Section 8: Domestic hot water
Table 28 Recommended minimum thermal efficiencies for domestic hot water systems
DHW system type
Fuel type
Heat generator seasonal efficiency (gross)
Thermal efficiency
Direct-fired:
new buildings
Direct-fired:
existing buildings
Indirect-fired:
new and existing buildings
Natural gas  30 kW output
90%
Natural gas  30 kW output
73%
LPG  30 kW output
92%
LPG  30 kW output
74%
Oil
76%
Natural gas
73%
LPG
74%
Oil
75%
Boiler seasonal
efficiency
Natural gas
80%
LPG
81%
Oil
82%
Electrically-heated:
new and existing buildings
100% assumed
Table 29 Recommended minimum controls package for gas and oil-fired domestic hot
water systems
DHW system type
Controls package
Direct-fired circulator:
natural gas and LPG
a. Automatic thermostat control to shut off the burner/primary heat supply when the
Direct-fired storage:
natural gas, LPG and oil
a. Automatic thermostat control to shut off the burner/primary heat supply when the
Direct-fired continuous
flow: natural gas and LPG
a. Outlet temperature of appliance controlled by rate of flow through heat exchanger.
b. High limit thermostat to shut off primary flow if system temperature too high.
c. Flow sensor that only allows electrical input should sufficient flow through the unit be
desired temperature of the hot water has been reached.
b. High limit thermostat to shut off primary flow if system temperature too high.
c. Time control.
desired temperature of the hot water has been reached.
b. High limit thermostat to shut off primary flow if system temperature too high.
c. Time control.
achieved.
d. Time control.
Indirect-fired: natural gas,
LPG and oil
a. Automatic thermostat control to shut off the burner/primary heat supply when the
desired temperature of the hot water has been reached.
b. High limit thermostat to shut off primary flow if system temperature too high.
c. Time control.
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Table 30 Recommended minimum controls package for electrically-heated domestic hot
water systems
Point-of-use
Local
Centralised
Instantaneous
Automatic thermostat control to interrupt the electrical supply
when the desired storage temperature has been reached.
Yes
Yes
Yes
x
High limit thermostat (thermal cut-out) to interrupt the energy
supply if the system temperature gets too high.
Yes
Yes
Yes
x
Manual reset in the event of an over-temperature trip.
Yes
Yes
Yes
x
7-day time clock (or BMS interface) to ensure bulk heating
of water using off-peak electricity. Facility to boost the
temperature using on-peak electricity (ideally by means of an
immersion heater fitted to heat the top 30% of the cylinder).
x
Yes
Yes
x
High limit thermostat (thermal cut-out) to interrupt the energy
supply if the outlet temperature gets too high. (Note: Outlet
temperature is controlled by rate of flow through the unit,
which on basic units would be by the outlet tap or fitting.)
x
x
x
Yes
Flow/pressure sensor that only allows electrical input should
sufficient flow through the unit be achieved.
x
x
x
Yes
8.5 Supplementary information on electric water heaters
Point-of-use
• Relevant standard is BS EN 60335-2-21:2003+A2:200833.
Instantaneous
• Relevant standard is BS EN 60335-2-35:2002+A2:201134.
Local
• For vented systems, relevant standard is BS EN 60335-2-21:2003+A2:2008.
• For unvented systems, relevant standard is BS EN 12897:200635.
Centralised
• Relevant standard is BS 853-1:1990+A3:201136.
• Bulk heating of the water should utilise off-peak electricity where possible.
• When using off-peak electricity a ‘boost heater’ should be fitted to allow ‘on-peak’ heating. The
boost heater should heat the top 30% of the cylinder and be rated to approximately 30% of the
main off-peak heater battery. The kW load will depend on the recovery time required.
33
34
35
36
48
BS EN 60335-2-21:2003+A2:2008 Specification for safety of household and similar electrical appliances. Particular requirements for storage water heaters.
BS EN 60335-2-35:2002+A2:2011 Specification for safety of household and similar electrical appliances. Particular requirements for instantaneous water heaters.
BS EN 12897:2006 Water supply. Specification for indirectly heated unvented (closed) storage water heaters.
BS 853-1:1990+A3:2011 Calorifiers and storage vessels for central heating and hot water supplies.
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• The heater battery should either be of removable core or rod element construction. Removable
core construction allows elements to be changed without removing the heater from the vessel or
draining the system. For removable core construction, the maximum element watts density should
not exceed 3 W/cm2 for copper tubes or 2.5 W/cm2 for stainless steel tubes. For rod element
construction, elements should be of nickel alloy 825 sheath, be U-bent and have a maximum watts
density of 10 W/cm2. Temperature control should be by means of ‘on/off’ control of the heater
battery utilising stage ramping for loadings above 30 kW. Thermostatic control is an ideal solution.
• The control sensor should be mounted in the cylinder at an angle of approximately 45° to the
heater and at a level just above the heating bundle. The over-temperature sensor (high limit) should
be mounted in the top 30% of the cylinder directly above the heater bundle. A manual reset
should be required in the event of an over-temperature trip.
• For loadings greater than 6 kW, temperature sensors should not be fitted to the heater bundle.
This is to prevent thermostat and contactor cycling which will lead to premature failure of the
equipment and poor temperature control.
8.6Heating efficiency credits for domestic hot water systems in new and
existing buildings
Heating efficiency credits are available for gas and oil-fired systems for the additional measures listed
in Table 31. If these measures are adopted, heating efficiency credits can be added to the heat generator
seasonal efficiency to give the effective heat generator seasonal efficiency, which is the value entered
into the accredited NCM tool in order to calculate the carbon dioxide emission rate for a building.
Effective heat generator seasonal efficiencyheat generator seasonal efficiencyheating efficiency credits
where the heat generator seasonal efficiency is:
• the thermal efficiency for direct-fired systems
• the boiler seasonal efficiency for indirect-fired systems.
Table 31 Heating efficiency credits for additional measures applicable to domestic hot water
systems
System type
Measure
Heating efficiency credits (% points)
All
Decentralisation
2, but not applicable to systems in new
buildings
Direct-fired
Integral combustion circuit shut-off device
1
Fully automatic ignition controls
0.5
Correct size of unit confirmed using
manufacturer’s technical helpline and sizing software
2
All
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Example: Using heating efficiency credits to improve the heat generator seasonal efficiency for a directfired circulator system
Step 1: Calculating thermal efficiency of direct-fired DHW system
• recovery rate of heater0.3830 litres/s
• gross input rate of heater83.5 kW
• specific heat capacity of water4.186 kJ/(kg.K)
• temperature rise of water inside heater50°C.
Using Equation 9:
Heater outputrecovery rate of heater in litres/secondspecific heat capacity of
watertemperature rise of the water
0.38304.1865080.16 kW
Using Equation 8:
Thermal efficiency (gross)output of the heater / gross input
• 80.16 / 83.50.96 (96%)
Step 2: Adding heating efficiency credits for additional measures
The heater has been sized to closely match the system demand by using the manufacturer’s sizing guide
and has fully automatic controls.
Table 32 shows how credits would be assigned in this example.
Table 32 Example to illustrate allocation of heating efficiency credits for a DHW system
Measure
Heating efficiency credits (% points)
Sized according to manufacturer’s guidance
2
Fully automatic ignition controls
0.5
Total credits
2.5
Effective heat generator seasonal efficiencythermal efficiency (gross)heating efficiency credits
962.598.5%
In this example, the value 98.5% would be entered in the NCM tool.
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Section 9: Comfort cooling
Section 9:Comfort cooling 9.1 Introduction
This section gives guidance on specifying comfort cooling for new and existing buildings to meet
relevant energy efficiency requirements in the Building Regulations. It includes guidance on using SBEM
to calculate the carbon dioxide emissions associated with comfort cooling in new buildings.
9.2Scope of guidance
The guidance covers the specification of refrigeration plant efficiency in terms of the seasonal energy
efficiency ratio (SEER), which is the value used by SBEM to calculate the carbon dioxide emission rate
for a new building. SBEM allocates standard correction factors37 to the performance of cooling plant to
account for the use of the different systems for distributing cooling to the spaces. Evaporative cooling
and desiccant cooling systems are not within the scope of this guidance.
9.3 Key terms
Cooling plant means that part of a cooling system that produces the supply of cooling medium. It does
not include means of distributing the cooling medium or the delivery of the cooling into the relevant
zone. It may consist, for example, of a single chiller or a series of chillers.
Cooling system means the complete system that is installed to provide the comfort cooling to the space.
It includes the cooling plant and the system by which the cooling medium effects cooling in the relevant
zone and the associated controls. This will in some cases be a complete packaged air conditioner.
Energy efficiency ratio (EER) for chillers is the cooling energy delivered into the cooling system divided
by the energy input to the chiller, as determined by BS EN 1451138.
In the case of packaged air conditioners, the EER is the energy removed from air within the conditioned
space divided by the effective energy input to the unit, as determined by BS EN 14511 or other appropriate
standard procedure. The test conditions for determining EER are those specified in BS EN 14511.
Part load energy efficiency ratio is the cooling energy delivered into the cooling system divided by the
energy input to the cooling plant. Part load performance for individual chillers is determined assuming
chilled water provision at 7°C out and 12°C in (at 100% load), under the following conditions:
Percentage part load
25%
50%
75%
100%
Air-cooled chillers ambient air
temperature (°C)
20
25
30
35
Water-cooled chillers entering
cooling water temperature (°C)
18
22
26
30
Seasonal energy efficiency ratio (SEER) is the total amount of cooling energy provided divided by the
total energy input to a single cooling unit, summed over the year.
37
38
The SBEM Technical Manual is available for download from www.ncm.bre.co.uk
BS EN 14511-2:2013 Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors for space heating and cooling. Test conditions.
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European Seasonal Energy Efficiency Ratio (ESEER) is the SEER of a cooling unit as determined under the
Eurovent Certification scheme.
Plant seasonal energy efficiency ratio (PSEER) is the total amount of cooling energy provided divided by
the total energy input to the cooling plant (which may comprise more than one cooling unit), summed
over the year.
9.4Comfort cooling in new and existing buildings
For comfort cooling systems in new and existing buildings:
a. cooling units should comply with European Commission Regulation No 327/2011 for fans driven by
motors with an electrical input power between 125 W and 500 kW, and Regulation No 206/2012
for systems with a cooling capacity of up to 12 kW, both implementing Directive 2009/125/EC with
regards to ecodesign requirements for energy-related products
b. the full load energy efficiency ratio (EER) of each cooling unit of the cooling plant should be no
worse than recommended in Table 33
c. controls should comply with BS EN 15232:201239 Band C and be no worse than recommended in Table 34.
Table 33 Recommended minimum energy efficiency ratio (EER) for comfort cooling
Type
Cooling unit full load EER
Packaged air conditioners
Single-duct type
2.6
Other types
2.6
Split and multi-split air conditioners  12 kW
2.6
Split and multi-split air conditioners  12 kW
SCOP ‘D’ rating for median temperature
range in BS EN 14825:201340
Variable refrigerant flow systems
2.6
Vapour compression cycle chillers, water-cooled  750 kW
3.9
Vapour compression cycle chillers, water-cooled  750 kW
4.7
Vapour compression cycle chillers, air-cooled  750 kW
2.55
Vapour compression cycle chillers, air-cooled  750 kW
2.65
Water loop heat pump
3.2
Absorption cycle chillers
0.7
Gas-engine-driven variable refrigerant flow
1.0
39 BS EN 15232:2012 Energy performance of buildings. Impact of building automation, controls and building management.
40 BS EN 14825:2013 Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors for space heating and cooling. Testing and rating at part load conditions
and calculation of seasonal performance.
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Table 34 Recommended minimum controls for comfort cooling in new and existing buildings
Controls
Cooling plant
a. Multiple cooling units should be provided with controls that ensure the combined plant
Cooling system
a. Terminal units capable of providing cooling should have integrated or remote time and
operates in its most efficient modes.
temperature controls.
b. In any given zone simultaneous heating and cooling should be prevented by an interlock.
9.5 Calculating the seasonal energy efficiency ratio for SBEM
The value of the SEER to be used in the SBEM tool can be calculated in a number of ways according to the availability of information and the application.
In general, where an industry approved test procedure for obtaining performance measurements of
cooling units at partial load conditions exists, and the cooling load profile of the proposed building is known, the SEER of the cooling unit is given by:
SEERa(EER 100%)b(EER 75%)c(EER50%)d(EER25%) Equation 10
where:
EERx is the EER measured at the load conditions of 100%, 75%, 50% and 25% at the operating
conditions detailed under the part load energy efficiency ratio in Section 9.3
and:
a, b, c and d are the load profile weighting factors relevant to the proposed application.
The following sections describe how the SEER may be calculated for the specific cases of:
• cooling units with no part load performance data
• unknown load profiles
• office-type accommodation
• other buildings with known load profile data
• multiple-chiller systems
• systems with free cooling or heat recovery
• absorption chillers and district cooling.
Cooling units with no part load performance data
For cooling units that have no part load data, the SEER is the full load EER.
Unknown load profiles
For applications where the load profile under which the cooling plant operates is not known but there is some data on chiller part load EER, then:
a. for chillers where the full and half load (50%) EERs are known, the SEER is the average of the EERs, i.e. the 100% and 50% are equally weighted
b. for chillers with four points of part load EER, the SEER is calculated using Equation 10 with each EER
weighted equally, i.e. a, b, c and d each equal to 0.25
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c. if the chiller used does not have data for four steps of load, then the weights are apportioned
appropriately.
Office-type accommodation
For applications in general office-type accommodation, the following weighting factors can be taken as
representative of the load profile:
a
b
c
d
0.03
0.33
0.41
0.23
These weighting factors are the same as those used for the determination of the European Seasonal
Energy Efficiency Ratio (ESEER). Most manufacturers publish ESEER figures and these can be verified by
reference to the Eurovent Certification website at www.eurovent-certification.com. The ESEER value is
then used as the SEER in the SBEM calculation.
Examples
1. For a single chiller with EER of 2.9 (known at full load only):
SEER2.9
2. For a chiller with 100% and 50% EERs of 2.0 and 2.5 respectively in a building with unknown load profile:
SEER2.25
3. For a chiller with unknown application load profile and part load EERs of EER100%2.89, EER75%3.93,
EER50%4.89 and EER25%4.79:
SEER0.252.890.253.930.254.890.254.794.125
4. If the same chiller is used in an office then the ESEER weighting factors are used:
SEERESEER0.032.890.333.930.414.890.234.794.49
Other buildings with known load profile
If the load profile is known from detailed simulation or prediction, the SEER may be derived from
Equation 10 above using appropriate weights and EERs at given loads.
Multiple-chiller systems
For plants with multiple-chillers, a plant seasonal energy efficiency ratio (PSEER) value may be calculated
based on the sum of the energy consumptions of all the operating chillers. In this case care must be
taken to include all the factors that can influence the combined performance of the multiple-chiller
installation. These will include the:
• degree of oversizing of the total installed capacity
• sizes of individual chillers
• EERs of individual chillers at actual operating conditions
• control mode used: e.g. parallel, sequential, dedicated low load unit
• load profile of the proposed building
• building location (as this determines ambient conditions).
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When these are known it may be possible to calculate a PSEER which matches the proposed installation
more closely than by applying the simplifications described earlier. This PSEER value is then used as the
SEER in the SBEM calculation.
Systems with free cooling or heat recovery
Systems that have the ability to use free cooling or heat recovery can achieve a greater SEER than
more conventional systems. In these cases the SEER must be derived for the specific application under
consideration.
Absorption chillers and district cooling
Absorption chillers may be used in conjunction with on-site CHP or a community or district heating
system. The carbon dioxide emissions are calculated in the same way as when using CHP for heating.
The control system should ensure as far as possible that heat from boilers is not used to supply the
absorption chiller. The minimum full load EER of the absorption chillers should be no worse than 0.7.
Where a district cooling scheme exists, lower carbon dioxide emissions may result if the cooling is
produced centrally from CHP/absorption chillers, heat pumps or high efficiency vapour compression
chillers. The district cooling company will provide information on the carbon dioxide content of the
cooling energy supplied, and this figure can then be used to calculate the carbon dioxide emission rate
for the building.
9.6Supplementary information
BS EN 15243:2007 41 provides additional guidance on calculating the seasonal efficiency of cold
generators and chillers in air conditioning systems. The guidance does not need to be followed to
meet relevant energy efficiency requirements in the Building Regulations.
41
BS EN 15243:2007 Ventilation for buildings. Calculation of room temperatures and of load and energy for buildings with room conditioning systems.
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Section 10:Air distribution 10.1 Introduction
This section gives guidance on specifying air distribution systems for new and existing buildings to meet
relevant energy efficiency requirements in the Building Regulations.
10.2 Scope of guidance
The guidance applies to the following types of air distribution system:
• central air conditioning systems
• central mechanical ventilation systems with heating, cooling or heat recovery
• all central systems not covered by the above two types
• zonal supply systems where the fan is remote from the zone, such as ceiling void or roof-mounted units
• zonal extract systems where the fan is remote from the zone
• local supply and extract ventilation units such as window, wall or roof units serving a single area (e.g. toilet extract)
• other local ventilation units, e.g. fan coil units and fan assisted terminal variable air volume (VAV) units
• kitchen extract, fan remote from zone with grease filter.
Gas and oil-fired air heaters installed within the area to be heated are not within the scope of this section.
10.3 Key terms
Air conditioning system means a combination of components required to provide a form of air treatment
in which temperature is controlled or can be lowered, possibly in combination with the control of
ventilation, humidity and air cleanliness.
Ventilation system means a combination of components required to provide air treatment in which
temperature, ventilation and air cleanliness are controlled.
Central system means a supply and extract system which serves the whole or major zones of the building.
Local unit means an unducted ventilation unit serving a single area.
Zonal system means a system which serves a group of rooms forming part of a building, i.e. a zone where
ducting is required.
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Demand control is a type of control where the ventilation rate is controlled by air quality, moisture,
occupancy or some other indicator of the need for ventilation.
Specific fan power (SFP) of an air distribution system means the sum of the design circuit-watts of
the system fans that supply air and exhaust it back outdoors, including losses through switchgear and
controls such as inverters (i.e. the total circuit-watts for the supply and extract fans), divided by the
design air flow rate through that system.
For the purposes of this guide, the specific fan power of an air distribution system should be calculated
according to the procedure set out in BS EN 13779:200742 Annex D Calculation and application of specific
fan power. Calculating and checking the SFP, SFPE and SFPV.
SFP

PsfPef
Equation 11
q
where:
SFPis the specific fan power demand of the air distribution system (W/(l.s))
Psf is the total fan power of all supply air fans at the design air flow rate, including power losses
through switchgear and controls associated with powering and controlling the fans (W)
Pef is the total fan power of all exhaust air fans at the design air flow rate including power losses
through switchgear and controls associated with powering and controlling the fans (W)
q is the design air flow rate through the system, which should be the greater of either the supply or
exhaust air flow (l/s). Note that for an air handling unit, q is the largest supply or extract air flow
through the unit.
External system pressure drop means the total system pressure drop excluding the pressure drop across
the air handling unit.
10.4 Air distribution systems in new and existing buildings
Air distribution systems in new and existing buildings should meet the following recommended minimum
standards:
a. Air handling systems should be capable of achieving a specific fan power at 25% of design flow rate
no greater than that achieved at 100% design flow rate.
b. In order to aid commissioning and to provide flexibility for future changes of use, reasonable
provision would be to equip with variable speed drives those fans that are rated at more than 1100 W
and which form part of the environmental control systems, including smoke control fans used for
control of overheating. The provision is not applicable to smoke control fans and similar ventilation
systems only used in abnormal circumstances.
42
BS EN 13779:2007 Ventilation for non-residential buildings. Performance requirements for ventilation and room-conditioning systems.
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c. In order to limit air leakage, ventilation ductwork should be made and assembled so as to be
reasonably airtight. Ways of meeting this requirement would be to comply with the specifications
given in:
i. B&ES DW/14443. Membership of the B&ES specialist ductwork group or the Association of
Ductwork Contractors and Allied Services is one way of demonstrating suitable qualifications, or
ii. British Standards such as BS EN 1507:200644, BS EN 12237:200345 and BS EN 13403:200346.
d. In order to limit air leakage, air handling units should be made and assembled so as to be reasonably
airtight. Ways of meeting this requirement would be to comply with Class L2 air leakage given in
BS EN 1886:200747.
e. The specific fan power of air distribution systems at the design air flow rate should be no worse than
in Table 35 for new and existing buildings. Specific fan power is a function of the system resistance
that the fan has to overcome to provide the required flow rate. BS EN 13779 Table A8 provides
guidance on system pressure drop. To minimise specific fan power it is recommended that the ‘low
range’ is used as a design target.
f. Where the primary air and cooling is provided by central plant and by an air distribution system
that includes the additional components listed in Table 36, the allowed specific fan powers may be
increased by the amounts shown in Table 36 to account for the additional resistance.
g. A minimum controls package should be provided in new and existing buildings as in Table 37.
h. Ventilation fans driven by electric motors should comply with European Commission Regulation No
327/2011 implementing Directive 2009/125/EC with regard to ecodesign requirements for fans driven
by motors with an electric input power between 125 W and 500 kW.
43
44
45
46
47
58
Ductwork Specification DW/144 Specifications for sheet metal ductwork. Low, medium and high pressure/velocity air system, B&ES, 2013.
BS EN 1507:2006 Ventilation for buildings. Sheet metal air ducts with rectangular section. Requirements for strength and leakage.
BS EN 12237:2003 Ventilation for buildings. Ductwork. Strength and leakage of circular sheet metal ducts.
BS EN 13403:2003 Ventilation for buildings. Non-metallic ducts. Ductwork made from insulation ductboards.
BS EN 1886:2007 Ventilation for buildings. Air handling units. Mechanical performance.
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Section 10: Air distribution
Table 35 Maximum specific fan power in air distribution systems in new and existing buildings
SFP (W/(l.s))
System type
New
buildings
Existing
buildings
Central balanced mechanical ventilation system with heating and cooling
1.6
2.2
Central balanced mechanical ventilation system with heating only
1.5
1.8
All other central balanced mechanical ventilation systems
1.1
1.6
Zonal supply system where fan is remote from zone, such as ceiling void or roofmounted units
1.1
1.4
Zonal extract system where fan is remote from zone
0.5
0.5
Zonal supply and extract ventilation units, such as ceiling void or roof units serving single
room or zone with heating and heat recovery
1.9
1.9
Local balanced supply and extract ventilation system such as wall/roof units serving
single area with heat recovery
1.6
1.6
Local supply or extract ventilation units such as window/wall/roof units serving single
area (e.g. toilet extract)
0.3
0.4
Other local ventilation supply or extract units
0.5
0.5
Fan assisted terminal VAV unit
1.1
1.1
Fan coil unit (rating weighted average*)
0.5
0.5
Kitchen extract, fan remote from zone with grease filter
1.0
1.0
* The rating weighted average is calculated by the following formula:
Pmains,1SFP1Pmains,2SFP2Pmains,3SFP3...
Pmains,1Pmains,2Pmains,3...
where Pmains is useful power supplied from the mains in W.
Table 36 Extending specific fan power for additional components in new and existing buildings
Component
SFP (W/(l.s))
Additional return filter for heat recovery
+0.1
HEPA filter
+1.0
Heat recovery – thermal wheel system
+0.3
Heat recovery – other systems
+0.3
Humidifier/dehumidifier (air conditioning system)
+0.1
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Example:
For a central mechanical ventilation system with heating and cooling, and heat recovery via a plate heat
exchanger plus return filter:
SFP 1.60.30.1 W/(l.s)
2.0 W/(l.s)
Table 37 Recommended minimum controls for air distribution systems in new and existing
buildings from BS EN 15232:201248
System type
Central mechanical
ventilation with heating,
cooling or heat recovery
Central mechanical
ventilation with heating or
heat recovery
Zonal
Local
Controls package
Air flow control at room level
Time control
Air flow control at air handler level
On/off time control
Heat exchanger defrosting control
Defrost control so that during cold periods
ice does not form on the heat exchanger
Heat exchanger overheating control
Overheating control so that when the
system is cooling and heat recovery is
undesirable, the heat exchanger is stopped,
modulated or bypassed
Supply temperature control
Variable set point with outdoor temperature
compensation
Air flow control at room level
Time control
Air flow control at air handler level
On/off time control
Heat exchanger defrosting control
Defrost control so that during cold periods
ice does not form on the heat exchanger
Heat exchanger overheating control
Overheating control so that when the
system is cooling and heat recovery is
undesirable, the heat exchanger is stopped,
modulated or bypassed
Supply temperature control
Demand control
Air flow control at room level
On/off time control
Air flow control at air handler level
No control
Supply temperature control
No control
Air flow control at room level
On/off
Air flow control at air handler level
No control
Supply temperature control
No control
48 BS EN 15232:2012 Energy performance of buildings. Impact of building automation, controls and building management.
60
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Section 10: Air distribution
10.5 Heat recovery in air distribution systems in new and existing buildings
Air supply and extract ventilation systems including heating or cooling should be fitted with a heat
recovery system. The application of a heat recovery system is described in 6.5 of BS EN 13053:2006+A1:201149.
The methods for testing air-to-air heat recovery devices are given in BS EN 308:199750.
The minimum dry heat recovery efficiency with reference to the mass flow ratio 1:1 should be no less
than that recommended in Table 38.
Table 38 Recommended minimum dry heat recovery efficiency for heat exchangers in new and
existing buildings
Heat exchanger type
Dry heat recovery efficiency (%)
Plate heat exchanger
50
Heat pipes
60
Thermal wheel
65
Run around coil
45
10.6 Calculating the specific fan power for SBEM
SBEM assumes a value of SFP for the fan coil system, so this figure should not be added to the SFP for the
fan coil units when entering the data into SBEM.
HEPA filtration is recognised as an option in SBEM. The pressure drop can be specified or SBEM will
assume a default value from the NCM activity database.
49 BS EN 13053:2006+A1:2011 Ventilation for buildings. Air handling units. Rating and performance for units, components and sections.
50 BS EN 308:1997 Heat exchangers. Test procedures for establishing the performance of air to air and flue gases heat recovery devices.
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Section 11:Pipework and ductwork insulation
11.1Introduction
This section gives guidance on insulating pipework and ducting serving space heating, hot water and
cooling systems in new and existing buildings to meet relevant energy efficiency requirements in the
Building Regulations.
The insulation of pipework and ducting is essential to minimise heating system heat losses and cooling
system heat gains. For cooling systems, it is also important to ensure that the risk of condensation is
adequately controlled.
11.2Scope of guidance
The guidance in this section covers insulation for the following types of pipework and ductwork serving
space heating, domestic hot water and cooling systems:
• pipework: direct hot water, low, medium and high temperature heating, and cooled
• ductwork: heated, cooled and dual-purpose heated and cooled.
11.3Insulation of pipes and ducts in new and existing buildings
Insulation of pipes and ducts serving heating and cooling systems should meet the following
recommended minimum standards. The relevant standard for calculating insulation thickness is BS EN ISO 12241:200851.
a. Direct hot water and heating pipework
i. Pipework serving space heating and hot water systems should be insulated in all areas outside
of the heated building envelope. In addition, pipes should be insulated in all voids within the
building envelope and within spaces which will normally be heated, if there is a possibility that
those spaces might be maintained at temperatures different to those maintained in other zones.
The guiding principles are that control should be maximised and that heat loss from uninsulated
pipes should only be permitted where the heat can be demonstrated as ‘always useful’.
ii. In order to demonstrate compliance, the heat losses shown in Table 39 for different pipe sizes and
temperatures should not be exceeded.
b. Cooling pipework
i. Cooling pipework should be insulated along its whole length in order to provide the necessary
means of limiting heat gain. Control should be maximised and heat gain to uninsulated pipes
should only be permitted where the proportion of the cooling load relating to distribution
pipework is proven to be less than 1% of total load.
ii. In order to demonstrate compliance, the heat gains in Table 40 for different pipe sizes and
temperatures should not be exceeded.
iii. Although unrelated to meeting relevant energy efficiency requirements in the Building Regulations,
provision should also be made for control of condensation by following TIMSA guidance52.
51
52
62
BS EN ISO 12241:2008. Thermal insulation for building equipment and industrial installations. Calculation rules.
TIMSA HVAC guidance for achieving compliance with Part L of the Building Regulations.
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Section 11: Pipework and ductwork insulation
c. Heating and cooling ductwork
i. Ducting should be insulated along its whole length in order to provide the necessary means of
limiting heat gains or heat losses.
ii. The heat losses or gains per unit area should not exceed the values in Table 41. Where ducting
may be used for both heating and cooling, the limits for chilled ducting should be adopted since
these are more onerous. (Heat gains are shown as negative values.)
iii. As with pipework, additional insulation may be required to provide adequate condensation
control, as detailed in TIMSA guidance.
Table 39 Recommended maximum heat losses for direct hot water and heating pipes
Heat loss (W/m)
Outside pipe
diameter (mm)
Hot water[1]
Low temperature
heating[2]
Medium temperature
heating[3]
High temperature
heating[4]
 95°C
96°C to 120°C
121°C to 150°C
17.2
6.60
8.90
13.34
17.92
21.3
7.13
9.28
13.56
18.32
26.9
7.83
10.06
13.83
18.70
33.7
8.62
11.07
14.39
19.02
42.4
9.72
12.30
15.66
19.25
48.3
10.21
12.94
16.67
20.17
60.3
11.57
14.45
18.25
21.96
76.1
13.09
16.35
20.42
24.21
88.9
14.58
17.91
22.09
25.99
114.3
17.20
20.77
25.31
29.32
139.7
19.65
23.71
28.23
32.47
168.3
22.31
26.89
31.61
36.04
219.1
27.52
32.54
37.66
42.16
 273.0
32.40
38.83
43.72
48.48
Note
To ensure compliance with the maximum heat loss criteria, insulation thicknesses should be calculated according to BS EN
ISO 12241 using standardised assumptions:
[1] Horizontal pipe at 60°C in still air at 15°C
[2] Horizontal pipe at 75°C in still air at 15°C
[3] Horizontal pipe at 100°C in still air at 15°C
[4] Horizontal pipe at 125°C in still air at 15°C
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Table 40 Recommended maximum heat gains for cooled water supply pipes
Heat gain (W/m)
Outside diameter of steel
pipe on which insulation has
been based (mm)
Temperature of contents (°C)
10[1]
4.9 to 10.0[2]
0 to 4.9[3]
17.2
2.48
2.97
3.47
21.3
2.72
3.27
3.81
26.9
3.05
3.58
4.18
33.7
3.41
4.01
4.60
42.4
3.86
4.53
5.11
48.3
4.11
4.82
5.45
60.3
4.78
5.48
6.17
76.1
5.51
6.30
6.70
88.9
6.17
6.90
7.77
114.3
7.28
8.31
9.15
139.7
8.52
9.49
10.45
168.3
9.89
10.97
11.86
219.1
12.27
13.57
14.61
273.0
14.74
16.28
17.48
Note
To ensure compliance with the maximum heat gain criteria, insulation thicknesses should be calculated according to BS EN ISO 12241 using standardised assumptions:
[1] Horizontal pipe at 10°C in still air at 25°C
[2] Horizontal pipe at 5°C in still air at 25°C
[3] Horizontal pipe at 0°C in still air at 25°C
Table 41 Recommended maximum heat losses and gains for insulated heating, cooling and dualpurpose ducts
Heat transfer (W/m2)
Heating duct[1]
Dual-purpose duct[2]
Cooling duct[3]
16.34
-6.45
-6.45
Note
To ensure compliance with maximum heat transfer criteria, insulation thicknesses should be calculated according to BS EN ISO 12241 using standardised assumptions:
[1] Horizontal duct at 35°C, with 600 mm vertical sidewall in still air at 15°C
[2] Horizontal duct at 13°C, with 600 mm vertical sidewall in still air at 25°C
[3] Horizontal duct at 13°C, with 600 mm vertical sidewall in still air at 25°C
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Section 12: Lighting
Section 12:Lighting 12.1 Introduction
This section provides guidance on specifying lighting for new and existing non-domestic buildings to meet
relevant energy efficiency requirements in the Building Regulations. There are two alternative approaches,
applicable both to systems in new buildings and to replacement systems in existing buildings.
12.2 Scope of guidance
The guidance in this section applies to the following types of lighting:
• general interior lighting
• display lighting.
12.3 Key terms
Office area means a space that involves predominantly desk-based tasks – e.g. a classroom, seminar or
conference room.
Daylit space means any space:
a. within 6 m of a window wall, provided that the glazing area is at least 20% of the internal area of the
window wall
b. below rooflights, provided that the glazing area is at least 10% of the floor area.
The normal light transmittance of the glazing should be at least 70%; if the light transmittance is below
70%, the glazing area should be increased proportionately for the space to be defined as daylit.
Space classification for control purposes53:
Owned space means a space such as a small room for one or two people who control the lighting –
e.g. a cellular office or consulting room.
Shared space means a multi-occupied area – e.g. an open-plan office or factory production area.
Temporarily owned space means a space where people are expected to operate the lighting controls
while they are there – e.g. a hotel room or meeting room.
Occasionally visited space means a space where people generally stay for a relatively short period
of time when they visit the space – e.g. a storeroom or toilet.
Unowned space means a space where individual users require lighting but are not expected to
operate the lighting controls – e.g. a corridor or atrium.
Managed space means a space where lighting is under the control of a responsible person – e.g. a
hotel lounge, restaurant or shop.
Local manual switching means that the distance on plan from any local switch to the luminaire it
controls should generally be not more than 6 m, or twice the height of the light fitting above the floor
if this is greater. Where the space is a daylit space served by side windows, the perimeter row of lighting
should in general be separately switched.
53
These definitions are given in more detail in BRE Information Paper IP6/96 People and lighting controls and BRE Digest 498 Selecting lighting controls.
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Photoelectric control is a type of control which switches or dims lighting in response to the amount of
incoming daylight.
Presence detection is a type of control which switches the lighting on when someone enters a space,
and switches it off, or dims it down, after the space becomes unoccupied.
Absence detection is a type of control which switches the lighting off, or dims it down, after the space
becomes unoccupied, but where switching on is done manually.
Lamp lumens means the sum of the average initial (100 hour) lumen output of all the lamps in the
luminaire.
Circuit-watt is the power consumed in lighting circuits by lamps and, where applicable, their associated
control gear (including transformers and drivers) and power factor correction equipment.
Lamp lumens per circuit-watt is the total lamp lumens summed for all luminaires in the relevant areas of
the building, divided by the total circuit-watts for all the luminaires.
LOR is the light output ratio of the luminaire, which means the ratio of the total light output of the
luminaire under stated practical conditions to that of the lamp or lamps contained in the luminaire
under reference conditions.
Luminaire lumens per circuit-watt is the (lamp lumens  LOR) summed for all luminaires in the relevant
areas of the building, divided by the total circuit-watts for all the luminaires.
LENI (Lighting Energy Numeric Indicator) is a measure of the performance of lighting in terms of energy
per square metre per year (kWh/m2/year), based on BS EN 15193:2007 Energy performance of buildings.
Energy requirements for lighting.
12.4 Lighting in new and existing buildings
a. Lighting in new and existing buildings should meet the recommended minimum standards for:
i. efficacy (averaged over the whole area of the applicable type of space in the building) and
controls in Table 42
OR
ii. the LENI in Table 44. The LENI should be calculated using the procedure described in Section 12.5.
b. The lighting should be metered to record its energy consumption in accordance with the minimum
standards in Table 43.
c. Lighting controls in new and existing buildings should follow the guidance in BRE Digest 498 Selecting
lighting controls. Display lighting, where provided, should be controlled on dedicated circuits that
can be switched off at times when people will not be inspecting exhibits or merchandise, or being
entertained.
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Section 12: Lighting
Table 42 Recommended minimum lighting efficacy with controls in new and existing buildings
Initial luminaire lumens/circuit-watt
General lighting in office, industrial and storage spaces
60
Controls
Control factor
Reduced luminaire lumens/circuit-watt
a daylit space with photo-switching with or without
override
0.90
54
b daylit space with photo-switching and dimming with
or without override
0.85
51
c unoccupied space with auto on and off
0.90
54
d unoccupied space with manual on and auto off
0.85
51
e space not daylit, dimmed for constant illuminance
0.90
54
ac
0.80
48
ad
0.75
45
bc
0.75
45
bd
0.70
42
ec
0.80
48
ed
0.75
45
General lighting in other types of space
The average initial efficacy should
be not less than 60 lamp lumens per
circuit-watt
Display lighting
The average initial efficacy should
be not less than 22 lamp lumens per
circuit-watt
Table 43 Recommended minimum standards for metering of general and display lighting in new
and existing buildings
Standard
Metering for general or
display lighting
a. kWh meters on dedicated lighting circuits in the electrical distribution, or
b. local power meter coupled to or integrated in the lighting controllers of a lighting or
building management system, or
c. a lighting management system that can calculate the consumed energy and make this
information available to a building management system or in an exportable file format.
(This could involve logging the hours run and the dimming level, and relating this to the
installed load.)
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12.5 Lighting Energy Numeric Indicator (LENI)
An alternative to complying with the efficacy standards in Table 42 is to follow the Lighting Energy
Numeric Indicator (LENI) method.
The LENI method calculates the performance of lighting in terms of energy per square metre per year.
The approach described below must be followed in calculating the LENI for a lighting scheme. The LENI
should not exceed the lighting energy limit specified in Table 44 for a given illuminance and hours run.
Design the lighting
The first step to energy efficient lighting is to design the lighting installation in a way that meets all of
the users’ needs for the space under consideration. Recommendations for appropriate illuminance values
and other lighting requirements may be found in BS EN 12464-1:201154, and in the Society of Light and
Lighting (SLL) Code for Lighting. The SLL Lighting Handbook provides practical advice on how to design
lighting for a number of different applications55.
Look up the lighting energy limit
In designing the lighting, a level of illuminance will have been selected as necessary for the tasks being
done in a particular area. It is also necessary to determine how many hours per year the lighting will be
needed. Once both the illuminance and the hours are known it is possible to look up the lighting energy
limit in Table 44. For example, a classroom in a school may be lit to 300 lux and used for 40 hours per
week for 39 weeks of the year, giving a total of 1560 hours per year. Values of 1500 hours and 300 lux give
a lighting energy limit of 7.70. Table 44 also gives day-time (Td) and night-time (Tn) hour values which are
used in the calculation of energy consumption.
If display lighting is used, then the lighting energy limit may be increased by the value given for normal
display lighting for the area of the room where display lighting is used. For example, in an entrance area
for a building there may be some display lighting in a small area around the reception desk but not in the
rest of the area.
Shop windows use a lot of display lighting and may use up to 192.72 kWh/m2/year if the window faces a
public road, and 96.8 kWh/m2/year if the window is in a shopping centre that is closed during the night.
Calculate the parasitic energy use (Ep)
If some form of lighting control system is used, then an allowance needs to be made for the energy used
by the control system, and the fact that the luminaires take a little power even if they are dimmed down
to give no light. An allowance of 0.3 W/m2 should be made for power used in this way. If the whole
lighting system is switched off when the room is not in use, then the power loss is only during the hours
of use. If the system is left on all the time then the power loss occurs for 8760 hours per year.
If no lighting control system is used, then the parasitic energy use is zero.
Determine the total power of lighting (Pl)
This is the total power in watts consumed by the luminaires within a space.
54
55
68
BS EN 12464-1:2011. Light and lighting. Lighting of work places. Indoor work places.
For further information, see www.sll.org.uk and www.thelia.org.uk.
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Section 12: Lighting
Determine the occupancy factor (Fo)
Fo allows for the fact that energy is saved if an automatic control system detects the presence or absence
of people in a room and switches off the lights when there is nobody using the room. If no automatic
control is used, then the occupancy factor Fo1. If controls turn off the lights within 20 minutes of the
room being empty, then Fo0.8.
Determine the factor for daylight (Fd)
Fd allows for the fact that if the lighting is dimmed down when there is daylight available, then less
energy will be used. If no daylight-linked dimming system is used, then Fd1. If the electric lighting dims
in response to daylight being available, then in areas with adequate daylight Fd0.8. Adequate daylight
may be found in areas that are within 6 m of a window wall or in areas where 10% or more of the roof is
translucent or made up of rooflights.
Determine the constant illuminance factor (Fc)
When lighting is designed, a maintenance factor (MF) is used to allow for the fact that as the lighting
system ages it produces less light. This means that on day one the lighting system is providing more light
than needed. Thus with a constant illuminance system, it is possible to under-run the lighting on day one,
and then slowly increase the power used by the lighting until the point is reached when maintenance
needs to be carried out by changing the lamps or cleaning the luminaires. Systems that control the
lighting in this way have an Fc0.9, and those that do not have an Fc1.
Calculate the daytime energy use (Ed)
The daytime energy use is:
Ed 
PlFoFdFcTd
1000
Calculate the night-time energy use (En)
The night-time energy use is:
En 
PlFoFcTn
1000
Calculate total energy (kWh) per square metre per year (LENI)
The total energy per square metre per year is the sum of the daytime, night-time and parasitic energy
uses per year divided by the area (A), as set out in the formula below:
LENI 
EpEdEn
A
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Table 44 Recommended maximum LENI (kWh per square metre per year) in new and
existing buildings
Hours
Illuminance (lux)
Display lighting
Total
Day
Night
50
100
150
200
300
500
750
1000
Shop
Normal window
1000
821
179
1.11
1.92
2.73
3.54
5.17
8.41
12.47
16.52
10.00
1500
1277
223
1.66
2.87
4.07
5.28
7.70
12.53
18.57
24.62
15.00
2000
1726
274
2.21
3.81
5.42
7.03
10.24
16.67
24.70
32.73
20.00
2500
2164
336
2.76
4.76
6.77
8.78
12.79
20.82
30.86
40.89
25.00
3000
2585
415
3.31
5.72
8.13
10.54
15.37
25.01
37.06
49.12
30.00
3700
3133
567
4.09
7.08
10.06
13.04
19.01
30.95
45.87
60.78
37.00
4400
3621
779
4.89
8.46
12.02
15.59
22.73
37.00
54.84
72.68
44.00
5400
4184
1216
6.05
10.47
14.90
19.33
28.18
45.89
68.03
90.17
54.00
6400
4547
1853
7.24
12.57
17.89
23.22
33.87
55.16
81.79
108.41
64.00
8760
4380
4380
10.26
17.89
25.53
33.16
48.43
78.96
117.12
155.29
87.60
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Section 13: Heating and cooling system circulators and water pumps
Section 13:Heating and cooling system
circulators and water pumps
13.1 Introduction
Heating and cooling water in HVAC systems of non-domestic buildings can circulate for extensive
periods and be responsible for considerable energy use.
13.2 Scope of guidance
This section provides guidance on specifying:
• heating system glandless circulators, both standalone and integrated in products
• heating and cooling system water pumps
to limit their energy consumption and meet relevant energy efficiency requirements in the Building
Regulations. The guidance covers circulators and water pumps when used in closed systems.
13.3 Key terms
Heating system glandless circulator means a pump used to circulate hot water in closed circuit heating
systems. The glandless (or wet rotor) circulator is a centrifugal pump with an integral motor and no
mechanical seal. It can have an integrated motor drive unit for variable speed operation.
Water pump (also known as ‘dry rotor’ or ‘direct coupled’ pump) means a centrifugal pump driven by an
electric motor and generally having mechanical seals. Common pump types include in-line, end suction
and vertical multi-stage. The first two are usually single-stage pumps having single-entry volute. By
design they can all be used as circulators for all HVAC applications depending on configuration and duty.
13.4 Glandless circulators and water pumps in new and existing buildings
Heating system glandless circulators and heating and cooling system water pumps in new and existing
buildings should meet the recommended minimum standards in Table 45.
Table 45 Recommended minimum standards for heating system glandless circulators and heating
and cooling system water pumps in new and existing buildings
a. In accordance with European Commission Regulation No 622/2012 (amending 641/2009) implementing Directive
2009/125/EC with regard to ecodesign requirements for glandless circulators up to 2.5 kW:
i.
From 1 January 2013, standalone glandless circulators, other than those specifically designed for primary circuits of
thermal solar systems and of heat pumps, should have an Energy Efficiency Index (EEI) no greater than 0.27.
ii. From 1 August 2015, standalone glandless circulators and glandless circulators integrated in products should have
an Energy Efficiency Index (EEI) no greater than 0.23.
b. Variable speed glandless circulators should be used on variable volume systems.
c. Water pumps should comply with the requirements of European Commission Regulation No 547/2012 implementing
Directive 2009/125/EC with regard to ecodesign requirements for water pumps.
d. If a water pump is used on a closed loop circuit and the motor is rated at more than 750 W, then it should be fitted with
or controlled by an appropriate variable speed controller on any variable volume system. On water pump booster sets
with an open loop circuit, the static head should be checked before an appropriate variable speed controller is used.
13.5 Supplementary information
Further information and guidance is available from www.bpma.org.uk where a list of approved
glandless circulators and water pumps can be found.
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Appendix A:Abbreviations
BER
BMS
BS
CHP
CHPQA
CO2
COP
DCLG
DECC
DHW
EEI
EER
EN
ESEER
HEPA
HVAC
LENI
LPG
MF
NCM
PSEER
QI
RHI
SAP
SBEM
SCOP
SEER
SFP
SI
SPEER
SPF
TER
TRV
VAV
72
Building carbon dioxide emission rate
Building management system
British Standard
Combined heat and power
Combined Heat and Power Quality Assurance
Carbon dioxide
Coefficient of performance
Department for Communities and Local Government
Department of Energy and Climate Change
Domestic hot water
Energy Efficiency Index
Energy efficiency ratio
European Norm (standard)
European Seasonal Energy Efficiency Ratio
High-efficiency particulate absorption
Heating, ventilation and air conditioning
Lighting Energy Numeric Indicator
Liquified petroleum gas
Maintenance factor
National Calculation Methodology
Plant seasonal energy efficiency ratio
Quality index
Renewable Heat Incentive
Standard Assessment Procedure
Simplified Building Energy Model
Seasonal coefficient of performance
Seasonal energy efficiency ratio
Specific fan power
Statutory Instrument
Seasonal primary energy efficiency ratio
Seasonal performance factor
Target carbon dioxide emission rate
Thermostatic radiator valve
Variable air volume
ONLINE VERSION
ONLINE VERSION
ONLINE VERSION
ONLINE VERSION
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ISBN 978 1 85946 535 6
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ONLINE VERSION
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