I spent about a year and a half in my 21ft Sunrader here in colorado. I was lucky and had a free spot adjacent to a garage with electrical connection. I would dump my black and grey tanks and fill with propane and about once a month. Winters I used bottled water and only ran the heat at the end of the day while eating and just before bed. I hung sleeping bags over the windows and used an electric bunk warmer for heat. The bunk warmer would about kill the house battery with one night of use. That was why the free electric was key. I wore fleece, hat and sox to bed. After a while I kind of wasn't affected so much buy the cold. When you needed wrmthe the furnace would heat the RV in minutes. I know your thinking, What was the coldest night?, Minus 6, everything was covered in frost the next morning.