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.
Step 2: Attach Fan to Roof
You can mount your solar panel to the exterior of the attic vent as long as it is in a WELL lit area that will receive direct sunlight. Bu sure and run your wires through the vent so you can connect it to the fan inside.
Mount your fan over any existing attic vent hole using the plumbers tape as you see here. You can be creative and make your own fixtures if you want. I would recommend some kind of insulation around the metal bands like insulation board or dynamatt. The metal bands will humm from the fan.
Connect the wires from the fan to your solar panel and you are done. It will run during the day and turn off when there is a lack of daylight.
You may want to add a switch to the circuit so that you can turn the fans on and off manually. You may also want to look into a thermostat that will turn the fans on at a certain temp.
Step 3: Comments
I hope everyone gets some good use out of this and I look forward to your comments. If you see something that could be improved, please share with everyone, but please be courteous about it.