I found you all last night and FINALLY have the solution to heating my 225 sq ft cabin I live in full time.
It finally dawned on me at 1am that what I need to do is fill in my recently framed 8-- 2' x 4' skylights with R-19 insulation and get a few 42 w Daylight bulbs for the winter.
I'd never thought of it before because I LOVE how bright my Hut is but the "skylights" are just clear polycarbonate roofing and the heat just goes straight up through them. This is my 8th winter here and I have done a lot of work to make it warm with sealing and insulating the rest of the roof.
This was the last piece of the puzzle I needed!
Thanks to you all!
Paul I grew up near you on a farm in Florence MT. (Now I'm on the Oregon Coast)