I have been heating a small bedroom with a 41" long space heater that has a thermostat for my Belgians that need 75F or higher. Obviously after 2 weeks of this thing heating the room even with the thermostat, my electric bill is not cheap. So I was thinking of building an insulated box about 48"Wx28"Hx26"W that could hold up to 4 fermenters/kegs, etc. The size is due to the size of the heater I have.
My question: What kind of insulation would you use to insulate this box? I've seen thin reflective type stuff. I know the about inch think foam stuff. And I don't think fiberglass would be a good option. Any ideas?
Oh and also, I'm assuming this is safe since I leave the heater on in the bedroom free from fabric, etc. and with the thermostat it shuts off when it gets to temp.