Using empty soda pop cans, a wooden frame, vacuum hose, and plexiglass you can build your own solar heater that boosts temperatures by 15 degrees!
I decided instead to take advantage of the south-facing side of the garage and build a solar furnace to collect some of that sunshine just bouncing straight off my garage. My dad built one years ago and said he recorded a 110-degree temperature differential between inlet and outlet. And I had enough scrap materials around the basement to do something similar.
