We bought our TH just for that reason- so the kids could have there "own" room when we go camping. Ours didn't have a heater vent in the garage but it did have a/c. I added a heat vent to the garage but honestly it didn't do much good. The garages don't seem to be insulated as well as the main living area. With that being said we picked up a small electric heater that has that knock over protection- it shuts off if knocked over or if it overheats. With one little heater going- it keeps the garage at 72* when it's 30* outside. I got the heater at Target- think it cost 21.99