It is to be -15 C tonight, which is normally as cold as it ever gets. March is normally a much warmer month???

Our two story house is very well insulated, with newer windows. As it is energy efficient, we use less heat to keep it warm. We have a mini split heat pump (with summer AC) in the lower level, and an oil fired, forced-air, furnace as our main heat source. Our windows are located to maximize winter sunshine (when it is cold, quite often the sky is clear), and our heating benefits from that.

The furnace is set for 62F nights (we like it cooler for sleeping) and 68F daytime. The mini split, for the most part, heats the house (it is set 81F winter 71F summer and is operating most of the time. The furnace kicks in once and awhile, if it is windy and really cold outside and also at 6 am in the morning, to give a blast of heat before we arise.

The basement is fairly warm, so,we overwinter outdoor plants under fluorescent lighting (they do well and reward us with abundant flowers).

In case the electricity goes out, I purchased a 6500 watt generator five years ago at Costco, as a back up to power the mini spilt. It is still unused in the box, as the power has not gone out since I bought it. I also have an indoor propane heater as a second back up, but never used it yet.