I have a 4-season. I'm sure some are much better insulated than others. This fall when I got back from a holiday, we had a cold snap for a week. Couldn't get the trailer serviced and had to turn on the furnace to keep it warm.
I was surprised how much propane that unit used in a week. The two 30 pounders where empty as well as a 20 pounder from my BBQ.