The average do it yourselfer probably could not build a furnace for their home, but there are small things you can build.

A solar heat exchanger is a simple wooden box with a 2x4 or 2x6 frame painted flat black with holes or slots cut into the box frame and the wall of the building it will be mounted to. Cold air will naturally be pulled in the bottom, heated and forced out the top. It is recommended a black mesh cloth be attached 2 -3 inches inward from the front, hanging from the top down. Mesh must be used to allow air to move freely through it. Cover the front with glass or plexiglass.Weatherproofing the box and the points it attaches to the building is highly recommended.

A simple wind turbine to power outdoor lights or small buildings can be made with an alternator and batteries for power storage. Using a General Motors alternator with a built in regulator eliminates the need for complicated wiring. Loop the two field wires together and run the power wire to the batteries. (10 - 12 awg ) Adding this to your windmill ornament or building a design of your own can help save a little money and make you a little more energy independent.