We are on our third AF990 (2008, 2012, 2018). They are very well insulated. We've stayed in it in very cold weather in CO, but were usually plugged in to electricity. So we could run the furnace as much as we wanted. It seems a tank of propane lasted more than a week, but we often augmented the furnace with a small ceramic space heater. The fridge and furnace are very efficient and insulation is good, so having two good sized propane tanks, we never ran out of propane before leaving a camping spot. Camping in the cold without hookups you naturally will run low on battery before running out of propane, but even that takes awhile. Never had any issues with the fridge in the slide. The AF990 layout has been around longer than any other RV, so it is tried and true. It suits us well. That said, I'm sure any modern, well-insulated camper with two propane tanks and two batteries will give you similar results.