High Performance Building and Navigating the Energy Codes

Understanding the Energy codes and How not only to meet but exceed the

codes

2009 or 2012?

• Energy codes are here to stay and becoming more and more prevalent

• State has mandated even if municipality has not

• Municipalities are all over the board as far as which code and what is being enforced.

• Most inspectors still don’t completely understand or misinterpret.

History of Energy Code• MEC 1992 - “Early” energy codes, very

complicated, DP windows required• IECC 98, 2000, ‘03 - “Strengthening”. SHGC of

0.4 required in cooling climates• IECC ‘04, ’06 – “Simplification” Fewer climate

zones, eliminate % windows• IECC ‘09 – Duct and envelope testing, lighting,

Stimulus money mandated states adopt• IECC IRC ‘12 – More challenging than ever

Energy Code Raising the Bar

• HERs Rating (Home Energy Rating) is compares to a 2006 code built house

• HERs score of 90 uses 90% energy of a 2006 code built house

• 2009 is 15% more stringent than ‘06• 2012 is 30% more stringent than ’06• 2015’s target is 50% greater than ‘06

Key differences

• HVAC duct testing is now required (state mandated)

• Vestavia Hills and Pell City have required in past for new construction and majority replacement of HVAC.

• Blower Door testing required for 2012. Checklist or blower door 2009

• Consolidated into IRC Chapter 11

Prescriptive changes

Prescriptive changes

3 Ways to meet Code

• Prescriptive – Do what code says (R20 R13+5 walls, R38 ceilings, R19/R5 floor/basement walls) Windows must meet requirement

• UA Trade off- Give a little, take a little. If you can’t meet in the walls, add more in ceiling/Floor(RES-Check, HERS) Windows must meet requirement

• Simulated Performance- Energy model shows your design uses less energy than a “code built house” (HERS rater typically involved)

Air Sealing

House Envelope

Typical Leakage Points

Air Leakage Prevention

Crawlspace insulation

Crawlspace Options

Closed Crawlspace

Duct Testing

Advanced Framing

• Typical wall framing averages at 27% framing factor. (27% studs/headers 73% insulation)

• Advance Framing is an engineered approach. Put studs only where needed to maximize insulation (16% wood 84% insulation)

• 24” oc. studs , Open Corners (California corners), Wall intersection (replace wall Tees with ladder Tees), Headers only when needed and sized correctly

Whole Wall Average R Values

Wood R Framing % Cavity R Insulation % Total Ave R

2x4x16oc 3.5 0.27 13 0.73 = 7.5

2x4x16oc+R5 8.5 0.27 18 0.73 = 13.8

2x6x16oc 5.5 0.27 18 0.73 = 11

2x6x24oc 5.5 0.16 18 0.84 = 13.6

2x6x24oc+R6.6 12.1 0.16 18 0.84 = 17.6

Properly Sized HVAC

• Manual J is now required (load sizing)• Rules of thumbs lead to trouble (500 sqft/ton)• Oversized HVAC increase costs and do not

dehumidify the house enough. • Take advantage of the more efficient envelope

and use a smaller correctly sized unit.

Resources

• www.apawood.org – advanced framing• www.energycodes.gov – REScheck• www.resnet.us - HERs Ratings• publicecodes.cyberregs.com – Online Codes• www.smartlivingenergy.com