After several summers of heat waves, B.C. is looking at ways to keep its residents cool. This summer, the B.C. government proposed a change to the province’s building code that would require all new homes to include at least one temperature-controlled room. The proposal was prompted by a 2021 heat wave that killed 619 people across the province.
“The new code proposes that all new homes in B.C. provide one temperature-controlled room that is designed not to exceed 26°C,” a spokesperson for the province’s Ministry of Housing said in an email. “This may be achieved through passive cooling such as architectural design, consideration of building materials, insulation, and solar reflectivity. It may also result in a cooling appliance being required in parts of the province, depending on summertime temperatures for the building location.”
The ministry is currently reviewing public feedback on the proposed change and expects to confirm the updated building code later this year.
The updated code will likely not require existing homes to be retrofitted with a temperature-controlled room. The ministry also confirmed that the code will only apply to “dwelling units intended for use in the summer months on a continuing basis,” meaning recreational cabins and cottages likely won’t be included in the updated code.
Experts, however, are concerned that the update could spike the number of air conditioning units, accelerating the effects of climate change and overloading the province’s power grid.
“If that’s what the policy is calling for then that’s actually a maladaptive climate policy,” says Edgar Dearden, the CEO of sustainable home design firm, GNAR Inc. in Whistler, B.C. “You need to do climate mitigation in hand with climate adaptation.”
That’s why Dearden advocates for sustainable cooling methods. “We are encouraging all our clients to make their houses naturally off-grid,” he says.
To keep dwellings sustainably cool, Dearden’s firm uses sizeable overhangs. Typically, these are roofs that extend two to two-and-a-half metres beyond the dwelling, shading its walls from the sun. “If you’ve got lots of overhangs around a building, it keeps the sun off the walls and creates these pockets of cool air that can be sucked into the house,” he says.
Dearden also avoids building houses with walls of windows. If they’re not shaded by a tree or an overhang, the sun will beat through the glass, heating the interior. “I talked to this one guy in Squamish,” Dearden says. “He has a lot of west-facing windows and whole sections of his house become unlivable in these heat waves.”
Instead, Dearden tries to have operable windows on opposite sides of the house so that you can have a crossflow of wind. He also places many of these windows beneath an overhang.
Another cooling strategy Dearden’s been experimenting with is opening certain windows. “We recently had a presentation from one of our passive house window suppliers. They showed us how tilt-and-turn windows can encourage passive cooling within a room—small openings lower down draw in dense cool air, while large openings up high allow the hot, less dense air to escape,” he says.
You can simulate this in two-storey houses by opening lower storey windows five centimetres and then opening upper storey windows 15 to 20 centimetres. When Dearden tried it at his own home, he found over several days that the midday temperature on the upper floor reached 26 to 27°C while the lower floor remained at 21 to 22 °C, even with outdoor temperatures soaring to 36°C.
If you do need to install a cooling device, Dearden recommends using a heat pump rather than an air conditioner, as it uses less electricity. Homeowners should also look into solar panels and batteries that can store energy in case the power grid does ever crash.
“If all you’ve got is solar panels and a battery, your house will have some power. You should get your electrician to wire your heat pump onto a separable circuit to power the life support systems of the house,” Dearden says. “That way, if there is a massive heat wave and the power grid goes down, you might not be able to do your washing, but the heat pump will be running, and you’re going to be okay.”