I haven't seen it hit -20F for years - and I'm in northern NH (just north of Mt. Washington).If you want to have some heat for those extreme cold days, -20°F to -30°F or more, there is a product called Sweeter Heater. . .
In the early '80s when I was home (here) from college one Christmas it hit near -40 overnight and topped out at -20 (I remember it because that was so unusual, maybe the coldest day in my life here!). In the 1990s when I lived in a valley in Danbury CT and the cold air sank in on clear still nights I'd call my parents in the morning and we would compare temperatures - several nights were -20F both places.
But I've lived back here for 4+ years now and I can't remember seeing it nearly that low once in that time. As far as I can remember over the last several years it rarely goes below -10F now.

I'm so sorry about the fire. 
). And I expect the OP will be fine, too, as most of New England is warmer than here, and parts that might be colder don't have many people (so probably not where the OP is)! 
