The 2012 IECC – or International Energy Conservation Code – ushers in some major changes to make homes and buildings more efficient. In this 5-part series, Newport calls out code provisions which will change how homes are designed and built.
Part 2: Blower Door Tests Will Be Required
Have you ever seen a “blower door test”? This building leakage test uses a pressure gauge, along with a tarp and a large fan in a dwelling’s doorway to measure the leakiness of the building shell. If you haven’t seen one yet – don’t worry – because they’ll become commonplace in areas where the 2012 IECC is adopted.
Why? Under the 2012 IECC, all homes are required to be tested and verified as having an air leakage rate ≤ 5 ACH50 (in Climate Zones 1 & 2) or ≤ 3 ACH50 (in Climate Zones 3 – 8. Testing of all homes?! Air leakage no greater than 3 ACH50 in most of the U.S.?!
These are big changes. But with change comes opportunity. Most newer homes are significantly more leaky than 3 ACH50 – in the range of 5 to 8 ACH50. But it’s not extremely difficult to ratchet down the air leakage, nor does it have to be expensive. Newport has worked with numerous builders on air sealing details and strategies that routinely produce new homes ≤ 3 ACH50 with a modest amount of spray foam, clear work scopes for contractors, and consistent attention to detail.
Who does the testing and verification part? Essentially it is left up to the code official, and the 2012 IECC calls out that the code official can require 3rd party testing. Energy Raters are a clear option for 3rd party verifiers.
Here are some tips for succeeding in the brave new world of thoroughly air-sealed, 100% tested new homes:
- If you’re going to fail, fail early. Have some new or recently built homes tested now to benchmark typical tightness levels. Then adjust air sealing practices accordingly before you’re building under the 2012 IECC and must meet the ACH50 target.
- Don’t go overboard. The 2012 tightness levels are a big jump, but can still be readily achieved with traditional materials. In other words, you don’t need to abandon wood framed walls or fill the entire envelope with spray foam.
- Don’t forget to breathe. People still need fresh air, and so do major combustion appliances. Our next blog covers mechanical ventilation under 2012 IECC (the people part); for combustion safety issues discuss options with your mechanical contractor. Power-vented or direct-vented furnaces and water heaters are more resilient in tighter homes, whereas atmospherically vented systems that rely on indoor air for combustion may also require make-up air.
- Who’s on first? Contractor coordination (or the lack of it) will make the difference in meeting tightness targets. Framers, window/siding, HVAC, electrical /low voltage, plumbing, insulation, drywall and (new to the scene) sprinkler contractors all affect each others work – - for better or worse. Inspect and test current projects at pre-drywall and at completion, identify leakage sites, and track these back to contractor coordination issues.
- You’re not just meeting code – you’re providing value! New homes under the 2012 IECC will be less drafty, more efficient, and generally quieter than most recently built or existing homes. Builders should market these advantages over the existing home market.