High Performance Building and Navigating the Energy Codes

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 %

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

12.1

0.16

18

0.84

=

17.6

2x6x24oc+R6.6

Total Ave R

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