OK, you can get a lot of heat from the engine in the rear bedroom when driving and for a few hours after stoping. When my kids were in the back bedroom watching movies while I drove we always ran the AC because it was hot. Of course we were always traveling in the summer also. I also ran the front one for my wife and I while driving. I also had the dash air on to. I don't like to be hot. I almost never ran the middle one, maybe if it was very hot. All 3 ran great on the 10K genet. or on the 50 amp when plugged in. I loved the genet it was a 3 cylinder kubota engine. 10K Onan quiet diesel. Awesome.