In reply to Tringa:
> The thing that concerns me about these dryers is where the dampness from the clothes goes, I assume it condenses on the walls of the room, which can't be good.
Yeah, I'd assume that you either want to stand it next to a dehumidifier or run it somewhere that's very well ventilated and set up to deal with a bit of moisture like a kitchen or a utility room. We've got a dehumidifier and the one downside is that you do need to get the room where it and the clothes are to a decent temperature before anything gets any drier, so I guess that something like this might be more efficient than heating the house if you're normally a "put on an extra jumper" type.
To be honest, though, when I saw the thread title I thought that someone had had the idea of sticking a heater and a dehumidifier in the back of a van and setting it up as a portable drying room at campsites in the Lake District. Now there's a free business plan if anyone wants one...