Each housing building requires heating when temperature falls below 10°C/50°F.

More advanced housing buildings require less heating energy per villager.

Resources that can be used for heating in order in which these will be used:

Housing appears to consume between 1.6-2.1 heating energy per day per building

(calculation performed using 7 log houses, with data taken every few days after 30 days of winter. vast majority showed 27-30 units of fuel consumed per 30 day reporting period, with some spikes up to 36 every so often)