My sauna is 3' x 5' with 7' ceiling and this heats it up to 180F in about 15 minutes. The control makes a pretty noticeable clunk as it connects and disconnects current as directed by the thermostat but that is a lot of watts to be switching. Think the swing switch in Frankenstein :-) I added rocks I bought at Menards but you need to be careful. Some will shatter when heated. They sell the right rocks for saunas elsewhere, I was just being cheap