Yeah, the space heater is what hit me - but it was really only Oct-Feb last year. This year has been so warm that I don't think I've seen nearly as much difference. If you're using the standard "blower" type heater, I strongly recommend switching to the oil-filled heater - I'm using mine on a 900w setting, which doesn't seem to be running even as constantly as the 1500w blower one was previously.