DIY Energy Efficiency – Solar Powered Attic Fans

This is a guest post written by Jonathan Cranos, Florida resident.

If you are trying to make a positive impact on the environment without having to make a huge monetary investment, here is a personal

story and idea that may be of interest to you: a solar powered attic fan!  I’m sure most of you are aware of the importance of attic insulation and ventilation for saving energy.  I live in a 1600-square-foot home in Lakewood Ranch, FL and for some inexplicable reason the builders decided to only install a 4 foot long ridge vent at the apex of my roof as they did with most homes out here.  I have plenty of soffit vents but practically nowhere for the heat to escape my attic given the minuscule 4 ft ridge vent. This fact combined with the cheap, under-powered and inefficient AC system builders use, meant I was unable to keep my home cooler than 80 degrees on the hottest summer days. My AC was running non-stop and my electric bills were astronomical!

One day I was roaming around a large chain home improvement store and came across a 10-watt solar powered roof vent turbine system for around $200.  I decided to take a chance and purchase the system to see if it would help my electric bill situation. All it required was a jig saw, a drill, a few roofing nails and some caulk (I bought the best roofing caulk I could find)  [Full disclosure - I'm am a fairly "handy" person, in fact my daughter calls me "Mr Fix-it" because I can and do fix just about anything around the house that breaks.]

I purposely placed my solar turbine on the roof over my garage where my pull down ladder is located. I decided this install location based on both ease of access and necessity.  This area of my attic has both a southern (great for solar) and western exposure and contains no attic insulation. It’s also the only area of my attic I can use for storage, but it was getting so hot up there (130+ degrees) that it was destroying most of the items I stored there.

The installation itself was quite simple and I think most people who are slightly handy could install this system. Honestly, the most difficult part of the project was deciding to cut an 18 inch diameter hole in my roof during the middle of a Florida summer (our monsoon season). I decided a logical place on my attic ceiling and I drew out the required 18-inch circle with the included template and cut the hole, no problem. I cut the hole from inside my attic, not from atop my roof, and when I poked my head through my new 18-inch hole in my roof to look around I see that a thunderstorm is about to hit my house!  They pop up FAST in Florida summers!  I immediately and fortunately had some blue tarp handy and was able to secure a cover over my newly cut hole to prevent the oncoming downpour of torrential rain from coming through my nice new hole.  As usual, the summer storm came and went in a matter of minutes and I was able to continue on with the installation. Installation from start to finish, aside waiting out the storm, was about an hour of time.

After completing the solar attic fan install, I immediately noticed a considerable drop in my electric bills amounting to $60-70 a month in summer and my AC could now cool my house to a comfortable level without constantly running. The attic temperature over my garage has dropped by 20-30 degrees. I have long since replaced my AC with a much more efficient one, but my solar roof vent has been up there running maintenance free and leak free for almost 15 years now.  My initial $200 investment has likely saved me thousands of dollars over the years and prevented countless amounts CO2 from entering the atmosphere.

The benefits of forced attic ventilation can be a debated subject.  This is mainly due to the fact that most home ceilings in reality are not perfectly sealed and electric powered attic  fan could potentially draw conditioned air from your homes interior into the attic. This would defeat the whole purpose and cause your AC unit to run even harder using more electricity. Electric attic fans use much higher CFMs (Cubic Feet Per Minute) than Solar turbine vents (800 CFMs) and studies have shown that electric powered roof turbines basically have no net energy saving advantages at all and can cause dangerous back-drafting of carbon monoxide gas into your home if you use gas appliances like I do. I installed CO detectors just in case but have had absolutely no problems.  The jury on solar attic fans may still be out for some, but not for me.  Bonus –  the solar fans are super quiet! You really can not hear them running at all, yet they do run, non-stop, day after day, year after year as long as the sun is out. It even runs when its slightly cloudy, just at lower speeds.

A solar powered attic fan may not be right for everyone’s particular situation but definitely worth looking into. There are many simple things one can do to cut down on using electricity in their homes from better insulation to LED light bulbs.  Also, most local utility companies will do a free energy assessment using high-tech thermal imaging devices to find energy leaks etc.  I would highly recommend having one performed and having a professional determine if a solar attic fan is right for your home.

 

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Over the last fifteen years, quiet variable speed fàns, small batteries and cheap highly intelligent small circuit boards have become available, my son in law uses a Raspberry Pi and weather data to sprinkle only as much as needed. Fans power consumption goes down by eight when cfm halve..So DIY


Comment by fran m farrell on January 21, 2017 7:46 am


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