How to build a portable solar gain heater? Answered
What I have in mind would be....a frame with wheels, with plexiglas on the front, black on the back, air intake on the bottom, black stacks of aluminum cans inside to funnel heat upward....and a flexible hose at the top to carry heated air into the house....not quite sure how to rig that up.
See, I've noticed that the outside of my dark green garage door will be hot to the touch even on a winter day, if it's sunny. But, the garage door is insulated and of course, the heat stays outside. This would have to be portable though, to roll away during non-winter, and in the rain...which since I lve in the Pacific Northwest, would be more often than not.