Experts say much of Vancouver's architecture is uniquely vulnerable to intensifying heat in Canada, because it was designed for milder weather, leaving the city with tens of thousands of buildings needing urgent upgrades. They say designers need to shift back to basic, sustainable building techniques to keep residents cool naturally, because relying on air conditioning won't be long-term solution.

"There's lessons in history," said Donald Luxton, who has worked as a heritage consultant in the city for 40 years. "We have to just think really hard about the environment and not try to conquer it, but work with it. And that's more, historically, how buildings were designed."

"In a place like Vancouver, where so much of what you're selling is location and view and access to nature ... more glass was a really big, big selling point," said Sara Stevens, an associate professor of architecture at the University of British Columbia.

The problem with so much glass, of course, is that it allows so much heat in, which must then be offset by air conditioning.

Luxton and Stevens said the city can go back to basics for retrofitting to undo its reliance on cooling technology. Features like heavy awnings, shaded windows, reflective exterior paint and more green space can reduce sun exposure.

The city has taken an incentive-based approach to encouraging renovations, rather than introducing hard and fast rules, because upgrades can displace residents in a city already contending with an affordability crisis.

B.C. has committed to reducing carbon emissions in the buildings sector by 59 to 64 per cent by 2030. The Pembina Institute, a non-profit energy think-tank, has estimated the residential sector will need $1.6 billion annually in retrofit incentives for the province to meet its commitment to be net-zero by 2050.