@mayintoronto controversial! It only gets to about -5°C here, the issue is the houses.

They're traditionally constructed like this: no insulation, no building membrane, just cladding and lining with an air gap between. You can see through gaps in the floorboards to the soil below. They're also full of big vents and open fireplaces, because the intention was to have fires in every room every day if you were a bit posh.

Edit: all this sounds like whinging, but imagine when this house flooded. The water went straight through those walls, flowed away between the gaps in the floorboards leaving minimal damage. Everyone with insulation/building wrap/plaster had to rip out their walls and ceiling in a hurry. We just kept living there.