Build a Solar Attic Fan for around $60 a piece.
1. Small automotive fan that you would normally find mounted to the dash of a car or truck. Walmart in Lubbock Tx sells them for $11 a piece. They are 10 Watt fans.
2. 10 Watt solar panel, or panel with appropriate output for multiple fans if you so choose. Fans MUST run on DC electricity. You can't use a fan that you would plug into the wall. I have three fans hooked up to a home made solar panel that produces around 50-60 Watts.
3. Plumbers tape and screws for securing your fans to the rafters.
4. Wire Strippers, Crimpers, and side cutters AKA Dykes.
5. Various wire connectors like...butt connecters
Step 1: Parts Prep
Remove the cigarette lighter adapter from the power cord that goes to your fan. Strip the wires back enough so that you can connect them to your solar panel. Connect the positive wire from the panel to the positive wire on the fan. If you do not know which one is which, connect the panel to the fan and go out in the sun. If the fan blows air forward, you have it wired correctly. If it pulls air inward, swap your wires around. Test again and proceed to step 2.