Achieving low-cost net-zero homes

How buildings should really breathe

In construction, you often hear it said that “buildings need to breathe.” What they mean is a home needs fresh air coming in to rejuvenate the indoor air quality and avoid problems associated with condensation. In older homes, fresh air enters through cracks and gaps (infiltration), but for at least two decades, the industry has known that “leaky houses are not the answer.”

New homes are built to prevent heat loss, with building envelopes constructed to be extremely airtight. There’s no “breathing” through gaps and cracks in a modern building envelope. Instead, air quality is maintained with a purpose-built ventilation system. A Heat Recovery Ventilation (HRV) system cycles fresh air in and out while retaining up to 80 per cent of the heat leaving the building.

The result is a very efficient home with great air quality—and peaceful and quiet to boot. “Because it’s so well insulated and airtight,” says Dan, “you can’t hear anything when it’s blowing outside. No whistling, no creaking at all.”

You might want to open a window just to break the silence.

But in a Stattonrock-built home, while there are lots of bright, sunlit windows, Dan will have recommended the owner reduce the number of opening windows. An operable window is more expensive and the moving parts mean it will be trickier to maintain the airtightness over time. And with a HRV, windows aren’t needed for ventilation.

“When you don’t need to have windows that open, don’t,” Dan recommends.

Net-zero doesn’t have to cost more

The advice on windows is just one example of Stattonrock’s approach to making net-zero homes affordable. It’s about carefully thinking through design decisions, choosing the right products, and doing the most they can with conventional materials.

“I really don’t believe that a net-zero home is meant to cost more,” Dan says. “We just have to put it together better.”

Everyone on the Stattonrock team is expected to take extra time to do things right, from using an extra box of glue for air sealing, to taking extra time to really understand each piece of equipment they install. The responsibility extends to every sub-trade. Air sealing a window, for instance, is harder when the frame isn’t straight. And if the window is crooked, the seals don’t line up, and the house isn’t as airtight as it should be.

That’s why Dan sees net-zero as a goal that pressures builders to master their craft. “As contractors and sub trades, we just have to do a better job. You do a decent job on site and the work will show.”

Dan has always been someone interested in mastering the details, in constantly improving the craft of home building. He started as a carpenter but now he’s got to make sure the whole system of a building fitting together. “From the first conversation through to every aspect there has to be attention to detail,” Dan says.

This is exactly the right attitude to bring toward net-zero building and the Step Code. Gone are the days of proscriptive rules. Now it’s about using creativity to reach the goals set by the code.

“There is more scope to be a creative problem solver now.” And Dan likes it that way. His philosophy is: “we’re the experts, we know what we have to achieve—we’d better just figure it out.”

The first Stattonrock net-zero home

In 2020-21, Dan gave the company a creative challenge by signing on for their first net-zero build. Dan’s home is located on the same idyllic rural stretch of Abbotsford as the Stattonrock workshop. At one point, he acquired the lot next door so they could build a home for family or friends. (What better way to make sure you like your neighbours?)

He also saw it as an opportunity to build net-zero. With a (literally) friendly client, the Stattonrock team would be able to test out designs and get familiar with new equipment and approaches. And it would be a chance to learn how to educate a client on the benefits of net-zero.

“They didn’t know much about the process or theory behind it and we spent time educating them about the benefits they would get by going down this route,” Dan recalls.

The clients went for an understated single-story home, ranch-style, with a finished basement. As Stattonrock’s first net-zero build, this straightforward design let them just focus on making sure all of the components worked together and performed well. They used triple-glazed windows and highly efficient doors. They added 2.5 inches of rigid insulation on the exterior walls and used insulated concrete forms for the foundation.

Dan took the lead on educating his sub-trades about what they needed to do to help Stattonrock achieve their goal of net-zero ready. “This project required the most integrated design to date, so we had the plumber, HVAC, an electrician and all of the builders in the same room together, figuring things out,” Dan recalls.

By instilling accountability in the sub-contractors (framers, carpenters, plumbers, concrete formers, and others), Dan believes everyone can do 10% better, enough to achieve the higher performance demanded by net-zero.

“It’s just about being smarter and thinking things through more, then taking a little more care and attention to the way everything is constructed. You don’t have to go with the most expensive materials, you just need to use a decent product and install it well.”