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