This past week I've been cutting and placing the 1" insulation boards. They are not spray foamed in yet so they can be easily removed when the house gets wired. Finished it up yesterday which happened to be the coldest night of the year so of course I wanted to sleep in it. I used my (Eden Pure like) heater, I don't know the off brand name. It was about 5f (-15c) outside and got to a high of 50f (10) inside holding a steady 48f (9c). Considering it's not foamed in and there is 2" more of insulation to be placed I was pretty happy. The 2" pieces will be placed after the wiring. I slept great by the way!