Cool Down with a Solar Attic Fan

solar_fan_roofOur prize for winning the 4th quarter of the Energy Showdown last year was a very cool solar attic fan.  It took us awhile to get around to installing it but we found plenty of motivation and dry weather in July.  I convinced my dad to come help, despite his preference to stay at ground level.  I took the fun job of cutting a hole in the roof (gotta love those sawzall projects) and then he helped me install the fan itself.

We were both a little surprised when the fan started spinning as he handed it up to me.  But it was sunny and the air temperature was above 80 and that’s all it takes for the fan to get to work.  The brand we got is called “the SunRise” from SRS (SunRise Solar, Inc) and it was made in Jordan, Indiana.  I’m happy to know we have some solar manufacturing in the state and so far I’m definitely impressed with the fan.

It’s a very simple one-piece unit that was pretty easy to install.  (For detailed instructions, check out this article from Home Power Magazine.)  My first step was to climb into the HOT attic and pick a location near the roofline and near the center of the attic.  I drilled a hole halfway between two rafters and left the drill bit in place. Then I climbed up on the roof, found my drill bit, stuck on the circular cardboard template that came with the fan, and used the sawzall to cut out a circular hole.  (I did nick the rafters on both sides but only a tiny bit.)

solar_fan_caulkAfter that, we pried the neighboring shingles loose so we could position the fan unit into place.  A few screws, a huge tube of caulk, and we were done!  We probably could have done the whole thing in under an hour but of course we had to take two trips to the hardware store – one for screws and a second one for a star-shaped drill bit that fit the star-shaped screws we had picked out.  Good times.

It’s hard to tell for sure how much of an impact the fan is having but it has definitely been running a lot.  The mechanics are pretty simple – there’s a photovoltaic panel attached to the motor but with a thermostat so that the fan will only run if the air temperature is above 80, which it has been for most of the last six weeks.  The goal is to pump hot air out of the attic, keeping it a little cooler and slowing down the amount of heat that seeps into our house.  I think it does reduce the burden on our air conditioner.  Yes, we have been running the air conditioner (set at a modest 81 or 82) although it’s mainly to keep the humidity down since we’re in Indiana swamp season (90% humidity nearly every day).  We also use fans, which make a huge difference.  Right now we only have a ceiling fan in the living room so we have a couple of box fans.  The trick is to minimize power use by only turning the fans on when you’re in that particular room since they don’t actually cool the air temperature; they just make you feel cooler by blowing away the layer of hot air around your body.  (Check out this post about staying cool from Mr. Electricity for a nice graphical explanation and some other non-AC cooling tips.)

Eventually we hope to add more ceiling fans but that will require an electrician.  For now, I’m planning to stick just with projects that involve cutting and gluing, which I think I mastered in kindergarten. this!

2 Responses so far »

  1. 1

    Emily said,

    August 6, 2011 @ 7:14 pm

    Oh, yay! You’ve gotten another toy I’ve wanted to test-drive. I will be eagerly awaiting news of its performance. 🙂

  2. 2

    Eric said,

    August 6, 2011 @ 11:32 pm

    I’ve heard mixed reviews on attic fans; I think you’ll want to be sure your attic is well-sealed (from the rest of the house) and that your soffit vents etc are clear, so you don’t draw conditioned air out of the house and up into the attic, which would be a bit of a waste 😉 (whether that’s AC-conditioned, or solar-furnace-conditioned…)

Comment RSS · TrackBack URI

Speak your piece