I have a fishroom 20x12.... 16 tanks at the moment...I have a heater in every tank which i want to change...I run a dehumidifier and it seems to put off some heat but not enough to keep my tanks at 79....so i'm also looking for a different way to heat the room.....Not a big fan of a space heater running all the time.....makes me nervous
79, unless you have an outside wall, than if the tank is against that wall the room will need to be warmer if it's cold out, cooler if it's hot out.
lights or a tank heater can change that.