Ok thanks. I think I might go ahead and order a thermostat just to be on the safe side. I might just set it at like 82 in case something goes wonky and it heats up more. I'ts been plugged in now for four days and the tank has held steady at 79 degrees. This time of year the furnace is set at 70 degrees and the room will stay that temp until the spring when outside temps warm up. Once spring/summer get here I'll just have to watch and see if I need the CHE.