I built a simple solar hot water heater for my home from mostly junk... I sold the idea to Back Home Magazine, a magazine that is based on homestead living in North Carolina... The system is really simple and not too costly in comparrison to a commercial solar hot water system... Also you don't need many plumbing skills or any permits... if anyone is interested simply reply and I'll explain the system.

I'm also in the process of finishing off my waste motor oil fired boiler that will run a homemade three HP steam engine to run a permanent magnet generator for charging solar battery bank when the sun or wind doesn't quite do the job.

Waste motor oil burns quite clean and is environmentally friendly... I get mine free and the same system can use waste cooking oil and could be adapted for home heating... If you are interested I will be happy to provide details and links to sources for research. It took me a few trials and errors but I can turn an old hot water heater tank glowing orange with my oil burner and the smoke coming out is less than from burning wood. Let me know.