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