Instructables
Picture of Solar Attic Fan
Build a Solar Attic Fan for around $60 a piece.

You'll need

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

 
Remove these adsRemove these ads by Signing Up

Step 1: Parts Prep

Picture of 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.
Battlespeed3 months ago

Anyone know how I would do this: Power two 12-V fans (about 10W each) from their battery packs, while using the solar panel to keep the batteries charged (instead of running the fans directly off the solar panel). I need to have the fans running 24x7, so they can't run directly off solar.

rpowell194 months ago

I know this is an older article but I want to add some things here. First this is a great idea and I was thinking of doing the same exact thing except a couple of things. First, I don't know why people are so into getting the hot air out of the attic. Yes the hot air does make your home hotter even on a 2006 home like mine that is build solid and has great installation. I am not saying getting the hot air out is bad thing but all you have to do is CIRCULATE the air in the attic and it will automatically cool down. With air there is friction, yes friction causes heat but when air is circulating it actually cools. When air cools it pushes the hotter air up. I can promise you that just by placing two to three of these small fans in your attic you will notice a huge difference in temperature after about 30 minutes. My house is new so it has the top ventilation at the peaks of the roofs. I really don't like it because there is not difference in the temp of my house or an older house that doesn't have this type. I would just install two to three fans in the attic to circulate the air and you will be fine. Its the same concept of having a fan in the house. The circulation itself cools down the air but causes the hotter air to rise.

blamb31 year ago
At Rand Solar, we offer solar attic fans of the highest quality. Our attic fans will save you large amounts of money on your electric bill each month and will nearly eliminate the need to run air conditioning at all! Not only that, our attic fans remove the water vapor and moisture in your air to increase the life of your entire roof system. Our solar attic fans are built with quality materials and run smoothly and flawlessly.

Rand Solar Attic Fans are very simple to install, it’s an easy do-it-yourself project. We have the full installation instructions on our website that you can read by going here: http://randsolar.com/installation/

Come take a look at our solar fans at http://randsolar.com
phrank704 years ago
Could you use a 10", 12 volt, 12.7 amp radiator fan?
Not with the panel indicated...
12Volt @ 12.7 amps works out to ~152 watts. (W = V x A)
So you'd need around a 160 watt panel or so.

That said, the fan should use less amperage depending on air restriction, etc. so if you plan to go that route you might want to measure the actual current (amps) draw under the intended use.
O2cool makes small battery powered fans. Some operate 6v, some @12. I've found the work well on 15w solar panel, even on overcast days. I got mine @ walmart for a good price
ddavis6623 years ago
Helpful info!
I was looking for a way to power a 12 volt fan to ventilate my camper.
I'm currently using trickle charger solar panel hooked to a 3 volt fan, but the panel will not power the fan unless it is in very direct sunlight.
I already have a 12 volt (lighter socket) fan andI just ordered a 10 watt panel from Amazon.com
I hooked the fan up to the panel and had the fan blowing hot air out of the bathroom vent in just a matter of minutes.
xavito3 years ago
Thanks for the great article! I am adding a battery (UPG Sealed Lead-Acid Battery - 12V, 1.3 Amps, Model# UB1213). Can you please tell me if I need to add a charge controller? Also, can you please explain the connection at the battery? Do I need a special connector?

Thanks again
fjpalacios13 years ago
Great idea, especially for homes in South Florida.....working on this today!
Thanks for the instructions!
zomfibame3 years ago
this is such a good idea, and nice n' simple.
kelseymh4 years ago

Very nice! Not all Instructables have to be long and complicated :-) This doesn't really have a lot of detail or "back story" to it, but it is a great DIY project.

Any chance you could include URLs (links) to your sources for the fans and the PV panels? That would make it easier for someone else to reproduce it.