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Howdy!
Has anyone had any recent(ish) experience with solar-powered fans?
Did it work for you, are you glad you did it, any lessons learned?
We're thinking of installing one or more on our roof, to get the hot air out. Insulating or painting the roof white isn't an option at the moment.
I'd like to also know where you bought the fan and how you got it installed.
many thanks
rbakker
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For $129 I bought a 30 watt solar panel and fan off of ebay (a few years ago). It moves 1550 cubic feet of air per minute in full sun. It moves less air under clouds but it does work when shaded. Because we have a hip roof there would have been no way to install it without cutting the roof and since this was a DIY project and I didn't trust my ability to not create leaks I used a different solution. I cut a piece of wood the same size as the board on the attic hatch and made a hole in the center to fit the fan. Then I mounted the solar panel and wired it to the fan. It pulls air from the house and blows it into the attic where it displaces the hot attic air. It works in two ways (pulling fresh air into the house, blowing hot air out of attic). Does it make a noticeable difference? I used to be able to put my hand to the ceiling and could feel the heat radiating from it. After adding the fan, no more heat. When the sun comes out and hits the metal roof is when the attic gets to be the hottest, but it is also the time when the fan kicks into high speed with the solar panel getting bathed in the same hot energy that is baking the attic.
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Thank you, terracore! The attic hatch is between the main part of the house and the attic, correct?
If so, how did you connect the fan to the solar panels on the roof? Apologies if I've misunderstood.
Blowing air from the house into the attic displaces the hot air in the attic, interesting.
Does your fan make noise and do the doors or windows rattle when it's on?
thanks again
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Sounds like terracore separated the fan and solar panel and is running the electrical wires between them through the ridgecap. This is actually a clever idea although I heard you shouldn't exhaust a bathroom vent fan directly into the attic because of the moisture. In this case it should be okay since there is no moisture. I myself put in a radiant heat barrier in my attic. This looks like aluminum foil but is a little tougher. You can get a roll for about $50 at HD. This has made a big difference. Like terracore I can put hand against the ceiling and notice how much cooler it is.
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There are some threads on solar attic fans (we have had a gable mount one for quite a few years, goes on when it is sunny & the thrmocouple reaches a preset temp...always been good & not too noticaeable as for as sound & such...we also have the reeflectix barrier)
Here is the most recent search thread that I found:
http://punaweb.org/Forum/topic.asp?TOPIC_ID=19915
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The system I bought was a fan and a solar panel as two separate items, not a contiguous unit. I purchased my own wiring to connect them. By attic hatch, I meant the piece of wood or drywall that is usually in a hallway or bedroom ceiling that provides normal access from the house to the attic. It probably has a real name but I don't know what it is. I'll try to illustrate through description; from our hallway there is the hatch in the ceiling that leads to the attic. I replaced the board that normally provides access to the attic with one with an approximately 12" hole that has the fan mounted on it. The fan sucks air from the hallway inside the house and blows it up into the attic.
The fan makes very little noise, it's almost silent. I think the rush of the air makes more sound than the fan itself and it does not rattle windows. By comparison our regular bathroom fans that vent outside move very little air and are very noisy. Also unlike a bathroom fan where there is a big square plastic cover on the ceiling that if you remove there is a much smaller (3 or 4 inch) fan blade system, on our solar system the entire 12" or so is fan blades that moves a lot of air.
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It's called an attic scuttle. What Terracore created is called a whole house fan. I have two that are wired into the house wiring. They are variable speed and on full blast can make the screens whistle. You also need to jam the doors open as they will suck them slammed shut. They're also 25 years old and are undoubtedly dated technology. With a climate that allows a solar version it seems a great idea.
Edit: Some newer ones are ducted into the attic with the fans at the end of the ducts putting the motor further away, thusly quieter. Probably irrelevant with a quiet solar fan. Here in S. Fl a solar version wouldn't suffice much of the year. Nothing besides AC does.
Interesting, at least for me: This YouTube shows one, an invisco (
http://invisco.com/products-2/ceiling-mounted-systems/), the author claims is the worlds first infinitely variable whole house fan. Strangely it looks and operates exactly like my 25 year old Emersons.
Pua`a
S. FL
Big Islander to be.
Pua`a
S. FL
Big Islander to be.
