In cities around the world, buildings generate more carbon emissions than anything else. In Vancouver, 55 per cent of all carbon pollution vents from buildings; in places that are significantly colder in the winter and hotter in the summer, like New York, building emissions can reach 70 per cent.

Older buildings are the worst culprits – they’re like clunker cars with multicylinder engines that consume a lot of gasoline. And just as vehicles with high fuel consumption are now a hard sell, buyers are also avoiding gas-guzzler buildings.