Our furnace stopped working about this time 3 or 4 years ago and that night and next were two of the coldest of the season so far. It was around zero at night and got to about 20 during the day. Went out Saturday night. Has HVAC guy out on Sunday and it was going to be $400 to fix a 15 year old furnace so on Monday we had a new one installed. We learned two things. This house is very well insulated because I never dropped below 60 and all we had was a few small electric space heaters..like $20 Walmart ones and it kept our 4,500 sq ft of heated space not too bad. Also the old unit was very undesired. It only cost a couple Grand. Sucked it was cold when it happened but we got new furnace and then this past year with the hail storm damage got a free brand new AC unit, siding and roof. ... So about $45 K of stuff that was going to need done for not a dime out of pocket. For once in our last 15 years we had some good fortune.