NC Energy Code RESNET Standards HERS Index HERS

NC Energy Code RESNET Standards HERS Index HERS

Presentation Overview:

NC Energy Code

RESNET Standards

HERS Index

HERS Verification Process

NC Energy Code Requirements

ENERGY STAR and NC Energy

Code in Alignment

RESNET Standards

HERS Index

A scoring system established by

RESNET in which the home’s

HERS score is based from the home’s energy efficiency.

Relatable to miles per gallon

The Department of Energy has given a standard home a rating of

100 (Reference Home).

Each HERS Index point represents a percentage point as compared to code.

The lower the score, the better.

Variables in a HERS Score

Square Footage

Number of Bedrooms

Home orientation

Properties of:

Crawl space

Frame floors

Exterior walls

Fenestration (windows, doors, etc.)

Ceilings

HVAC & DHW efficiencies

Mechanical ventilation

Envelope & duct leakage

Lights & appliances

Solar & geothermal

Strong HERS Index Drivers

HVAC & ducts in conditioned space

Ductless mini-split systems

Tight envelope with mechanical fresh air

Lower window to wall and floor ratios

Continuous insulation

Slab edge insulation

Hybrid & tank-less water heaters

Radiant barrier roof sheathing

Renewable / Solar Energy

High efficiency lighting

High efficiency HVAC

Preliminary

Rating

HERS Rating

Verification Process

Rough

Inspection

Final

Inspection

Preliminary

Rating:

Plans & Inputs

Preliminary

Rating:

Energy Modeling

An analysis of the home’s building plans along with the energy efficiency specifications.

This process also involves the use of both, a 3D modeling & energy modeling software.

This analysis yields a projected, preconstruction HERS score for the builder.

Preliminary Rating:

Reports

Energy model confirms compliance with desired program or code

Predicts HERS Index, rebate amount, & energy and $ savings

Verification

Process:

Two Rough Inspections

1.

Framing Walk - Identifies air sealing and framing air barriers before insulation and other trades.

2.

Insulation Inspection- assesses installation quality and verifies other aspects of air sealing and air barriers.

Interior and Exterior

Air Barriers

Interior Air Barriers are usually the sheetrock. Sometimes though the drywall will turn and not follow insulation and that Interior Air Barrier must be put back on.

Exterior Air Barriers are usually sheathings and housewraps but sometimes (knee walls in particular) the exterior sheathing must be put back on.

3.

4.

1.

2.

5.

6.

Needed: 6 sided wall assemblies

Left Stud

Right Stud

Top Plate

Bottom Plate

Exterior Sheathing

Interior Drywall

Rough Inspection

Air Barriers &

Air Sealing

Air Barriers are solid materials that don’t allow air to pass through them.

Air Sealing fills seams and gaps with caulk or foam.

Knee Walls

Knee Walls are defined as a vertical wall with conditioned space on one side and attic on the other.

Knee Walls

Must have 6 sides, full depth

Knee Walls

Needed:

Blocking under knee walls

Knee Walls

Needed:

Blocking under knee walls

Chases

Needed:

Caps need to be installed.

Air seal with fire-rated caulk to finish job.

Dropped Ceiling

Needed:

Caps

Cantilevers

Needed:

Blocking

Garage Band Joists (Also Cantilevers)

Needed:

Blocking

Penetrations

Needed:

Air Sealing

Plumbing

Pipes

Electrical

Wires

Threaded

Rod

Data Cables

Air

Seal

Misc. Plate

Penetrations

Penetrations

Windows &

Doors

Needed:

Air Sealing

NOT Needed:

Fiberglass Chinking

Air Sealing

Sill Plates

Air Sealing

Top Plates

Interior Air Barriers

Needed at:

Shower

Tubs

Interior Air

Barriers

Fireplaces

Stairs

Double

Walls

Interior Air Barriers

Shower and Fireplace

Interior Air Barriers

Under stairs at exterior & garage walls

Baffles

and

Insulation Dams

Needed at:

Adjacent porches

Bonus room knee wall

Note:

Your Framer can help where wall is parallel to truss

.

Common Walls

Needed:

Air Sealing

NOT Needed:

Fiberglass Chinking

Insulation

Inspection

Insulation Installation

Floor Insulation

Properly supported and in contact with subfloor above

Spray foam can even have installation issues

Options to Consider

The Framing Factor

Advanced Framing Techniques

Verification

Process:

Final Inspection

Field Verification of rated features in homes confirming energy specs in preliminary rating.

Includes 2012 NC Energy Code blower door and duct testing.

Blower door testing, or visual inspection, & Duct Blaster testing

Data collected entered into

REM/Rate software to produce

“Confirmed Rating”.

Blower Door Duct Blaster

Final Inspection

Air Barriers &

Air Sealing

HVAC Boots caulked to drywall.

Ceiling Light fixture boxes sealed to sheetrock.

ICAT recessed lighting sealed to sheetrock.

Exhaust Fan boxes sealed to sheetrock.

Scuttle Access gasket in place and insulation attached to panel.

Drop Down Attic Stairs have weather-strip and R-5 Continuous.

Weather-stripping installed exterior doors and attic doors.

HVAC

Supply & Return

Needed:

Air Sealing

ICAT Can Lights

Benefits of HERS Ratings

Marketing Opportunities

Energy-efficient New Homes Tax Credit for Home Builders: $2,000

ENERGY STAR & Green Building Programs

Compliance

Reporting:

Energy code compliance

Program compliance

ENERGY STAR

Tax credit compliance

NC HERO code compliance

Compliance:

Energy Efficiency Certificate

Passing blower door test confirms homes are reasonably tight at 5

ACH or less (4 ACH for HERO)

Passing duct system test confirms home’s HVAC and duct system is reasonably tight at 6% or less

(4% for HERO)

Certificate posted to display compliance in electrical panel

Compliance

Reports:

ENERGY STAR and HERC

Confirmed Rating produces

ENERGY STAR Certificate

Confirmed Rating produces Home

Energy Rating Certificate

Heating and Cooling Costs estimated

Energy and dollar savings quantified

Green house gas emissions reduction quantified

Energy Efficient Mortgages

New Homes

Also known as an EEM, they aid in the process of qualifying a borrow for a loan to purchase homes that have been rated energy-efficient. An EEM is easily explained by realizing that the person will have more disposable income and can afford a larger house payment.

Energy Improvement Mortgages

Existing Homes

Also known as an EIM, allows for purchaser to borrow additional money for energy efficiency improvements that will be wrapped into mortgage.

Benefits

The savings are added income, improving debt-to-income ratio.

A rating shows the value of the added energy-efficient features by estimating monthly savings.

The home’s value is increased from the energy-efficient features.

May have reduced loan fees.

NC HERO Code and HERS Ratings

Slab Edge Insulation

Slab Edge Insulation

2x6, R3, SIS, Other?

NC HERO Code and the HERS Index

HERS Index is pointed towards the

2006 IECC

2012 NC code is based on the 2009

IECC which is roughly 15% more efficient than the 2006 IECC

HERO code is designed to be roughly 30% more efficient than

2006 or 15% more efficient than our current code

Thus home built to HERO code should have HERS index of 70

The lower the score, higher the rebate incentive.

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