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Earlier blower door testing can mean big savings

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"Measure twice, cut once." If you're in construction, you probably had that trained into you early. So it's interesting that one of the best measures of a home's energy efficiency is commonly done only at the very end of the build — when all the "cutting" has already been done.

Blower door testing checks a home's air tightness — a key element of energy efficiency. It's done when construction is complete to provide an EnerGuide rating for the home. But when energy efficiency is a priority, smart builders want to know their test scores when there's still time to improve their grade.

Mid-construction testing saves money, time

"Back a few years ago, we used to bring in our energy evaluator to test just before the closing of a house," says Serge Desjardins, director of green initiatives for Minto Communities, (Ottawa) one of the most experienced ENERGY STAR® builders in Canada. Today, the company uses mid-construction blower door testing, which helps avoid surprises and ensures that they're ready to meet energy-efficiency targets early on in the process.

Minto takes energy efficiency seriously. They build over 1,000 homes a year in Ottawa, Toronto, and Florida. Minto has focused on energy usage since it first offered an "energy miser" home in the 1950s. Now, all Minto homes are ENERGY STAR minimum standard (achieving EG80 or better), with many LEED-certified. And mid-construction blower door tests are one of ways they've arrived there.

The more you can catch before you drywall, the better, says Desjardins. Air showing up in an outlet could actually be coming in the other end of the house. It's much more costly and time-consuming to fix problems after drywall has gone in.

Matheo Dürfeld of Whistler-based Dürfeld Constructors agrees. Since building Canada's first registered Passive House for the 2010 Olympics, he has continued to focus on energy efficiency techniques in his builds — including mid-construction blower door testing.

Simple repairs still possible

"If you just do a blower test at the end of the project you're pretty limited as to how you can rectify anything," says Dürfeld. Mid-construction blower tests help you retain access to your air/vapour barrier and other areas that can have a big impact, he points out. Simple repairs like caulking or taping are still possible.

Both agree that while mid-construction testing is invaluable, it's just one part of a comprehensive approach to energy efficiency. Dürfeld says paying attention at the pre-construction phase is important. "There's no single method of creating an air/vapour barrier; there are lots of ways to do it," he says. "But once you adopt one, then you really have to follow it all the way through and be consistent, or it can be hard to correct."

Culture of energy efficiency brings huge benefits

At Minto, energy efficiency has been built into the culture. Contractors are aware that they need to seal any penetrations through the exterior or interior envelope. Given the size of the company, Minto has also invested in its own blower door equipment, and does its own mid-construction testing, something Desjardins says has contributed to the company's continual learning about air tightness.

"Air leakage: I call it the animal to master," he says. "When we come up with new products, we always seem to find new ways for homes to leak. But like anything else, if you put the time upfront and you keep learning as you go, the benefits are huge, because afterwards it's a lot bigger headache to deal with."