In our Old House, we heat with two DV stoves. It sits on pillars and has a crawl space (with about 3-4' space) and a dirt "floor". It is now a rental since we bought the Cottage. While we lived there, we used to leave the hot water running just a bit during the winter to keep the pipes from freezing. Actually, when we bought it, it had a gravity heater in the floor and never had a problem with freezing pipes. After we took that out, we had to leave the water running. This isn't a solution for a tenant. We put heat tape on one pipe (longest run of hot water, the one that we typically had a problem with when one of us forgot to leave the water dripping), but they're like a spider web, there is NO way to tape all of them. We can't run ducts, since there's no central heat. Has anyone ever used a crawl space heater? I've seen them online but can't really find reviews, just people saying to run a duct or use heat tape, lol.