This may come as a shock. We have a lightly modified (some insulation improvements in some areas, some new windows) mobile home made in 1983 that has a huge sou

This may come as a shock. We have a lightly modified (some insulation improvements in some areas, some new windows) mobile home made in 1983 that has a huge south facing window area. It has central forced air heating but only a wall shaker air conditioner for summer. We leave the furnace thermostat set to 65F when we’re there. On mild clear winter days (-15C or so), we have had to open the windows because the place has climbed above 80F! At night the furnace will run because the insulation is generally nothing special, but there’s a ton of solar energy available to heat the house directly. I’m kind of curious now to try turning the furnace off overnight just to see how cool it gets… Note: it sucks in the summer but because of our latitude we can quite effectively build an awning that will keep the windows in shadow during the summer and let all that light in during the winter. That is this year’s project for the spring :)