I have a 12x12 insulated room I built in my barn and I use a little box heater 1250-1500 watts adjustable thermostat on it and it will warm the room up very quickly. I also found out if I plug in a 200 watt old style clear light bulb the ones that get very hot to the touch that it will keep the room at 42 degrees when the outside temp is 10 degrees like this morning.
