The way this all started, at the previous Cold House, was that I decided to seal off the kitchen / sofa room– a space of about 150 sq ft– as a “thermal bunker”, and just kind of live in there for the winter. It worked well. At the New Cold House, we have tried to do the same, closing off (unheated) guest rooms and isolating the upstairs with quilted barriers in the doorways. But the floor plan here is a bit more open, and the new “bunker” is now more like 375 sq ft. Not quite the same cozy feeling.
Anyway, all along I’ve been fantasizing about having a micro-space that could be quickly and ultra-efficiently heated to high temperatures. The idea is someplace to go that just warms your body, without having to warm much of the house. This would be great on those occasions when you’re just getting a little too cold, starting to shiver, can’t quite reclaim normothermia– to get warm, fast, without starting a fire and warming the whole bunker. It would, in other words, be a super-bunker.
Or, in other other words: a sauna. Or something like it. There are lots of places we could build one, theoretically, but given my level of expertise in finish (Finnish?) carpentry, the cellar is the logical answer: even bare 2×4’s and plywood would improve the general aesthetics of this cellar. I would build it out of rough stud walls with heavy insulation and cedar paneling on the inside. It would be about 15 sq ft (100 cu ft) and would only need a tiny sauna heater, say 3kW. I think it would be capable of reaching 170ºF in about 10 minutes, using about 6¢ of electricity. And with a craftily-designed adjustable vent system, at least at least a good part of the cellar-sauna heat could wind up in the bunker after use.
Has anyone built such a thing, or something similar?