We live at the beach, so it doesn't get terribly cold here. But, since we live at the beach, all we have are window unit air conditioners, and only two of them have built-in heaters. We chose this to keep the chill out of the rooms that didn't have heaters and it is excellent. I don't know if it will heat 1,000 sf., but it easily warmed our room up this morning (the first time we used it), and it was absolutely the quietest fan-blown heater I've ever heard -- or not heard -- and it had no problem warming up our living room, which has concrete walls and a 10-foot ceiling.