[wingnut60]

Glenn,
I can't explain it either--made it a month in Denver Feb '19 at -11 and below freezing for several days. Took awhile, but basically having a space heater in the basement and a light bulb in the service bay, kept us going. Had several different freezeups, before figuring out the cold spots, but no permanent damage. I don't care what the mfgs say is "4-seasons" or "Arctic Package" or what--it isn't just routine to live in a fiver at those temps and length of time.