Report Heat transfer theory in Theory articles Posted December 4, 2011 Would a small fluid based radiator plus a low speed fan be more efficient. Our house growing up was hot water heated and quite efficient. Also a friend of mine heats his small home with an electric oil filled radiator. Certainly the wattage for a room heater is around the 900-1500W range, but I would think for the size of this gentleman's application it could be lower. Though admittedly I've not yet run the numbers.