Solar panel for Attic Vent Fan

Old 10-21-03, 02:38 PM
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Solar panel for Attic Vent Fan

I would like to add an ventilation fan for my attic and would like to know if anyone has used a small solar panel to power one of these fans? My theory is that if the sun is not shining then there is no need for the fan to run anyway (I am in Louisiana - the summer is a bigger concern than winter).

A small solar panel should not cost a lot ...

Has this been done? Know of any vendors?

Also, my home is shaped like a "C" (really it is an "E" without the middle bar). The main part of the attic is 80 ft long and maybe 25 feet wide and 12 ft tall in the middle. This might require multiple fans. If I had one fan at each end both blowing air outward will this be a problem? I have heard of fans sucking air from inside the living area if not properly sized. Is this true? I have a continuos ridge vent. Should the fan at one end blow and the fan at the other end suck?

Old 10-21-03, 03:19 PM
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If you have a vent ridge, you should have the proper amount of soffit and gable end vents to provide the air flow for the attic. This should provide plenty of ventilation without the expense of adding fans.

My vent ridge provides 1.5 square feet of opening for each 1 foot of run. A 50 foot long vent would provide 75 square feet of open space for the attic air to vent through. You should have an appropriate amount of soffit or gable end vents to provide air flow satisfying the requirements of the attic's space.

If the ceiling is hot, then you might take a look at your insulation.

If you want to install fans, they won't pull air from the house. Not with a vent ridge installed. The solar panel is a an interesting idea. How large of a panel would be needed to ventilate your attic?
Old 10-21-03, 06:18 PM
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This is one site that shows a solar powered attic fan. There are quite a few others out there, just search the web for them. Most of them are combined units where the solar panel is integrated with the fan to form one unit. I like the one shown above because the fan and panel are separate. So if it the sun shines most of the time on the front of the house, you can still have the fan on the backside with the panel on the front getting the sun.
Old 10-22-03, 09:45 AM
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marc -

solar powered fans sound good.

here's the issue, you want to bring air in low and bring
it out high. in other words the hot air in your attic,
which rises (because it's hot will go out the top,
ridge vent, pulling in cool air through the soffit vents.

generally, I'd design the area of the soffit vents to
be slightly larger than the ridge vent.

Have you considered roof turbines? they don't use
any power at all.

if you want to put an opening at one end and at the other,
and run one fan one way and the other the opposite,
consider prevailing winds in your area, as to which one
runs which way. it'd be better to have the fans working
with the wind than against.

in terms of the fans sucking air from the living area, i don't
think you should worry about that. the air flow in
the attic is so small that this is not a concern.

now, if you put a jet engine up there.....
Old 10-22-03, 02:13 PM
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solar fans

Short and sweet of it . Used them on a boat . Not worth a D***and they got lots of sun
Put a power vent fan there if you need one .Dont cost that much to run . When your on A/C we look at the power fan as worth a 1/2 ton of A/C ED
Old 10-25-03, 05:13 PM
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Lightbulb Turbines

I also am a big fan of the turbines, they will keep your attic just as cool as the solar attic fans and cost a LOT less.

The solar attic fans simply don't have enough power to do much good, most have 25W motors !!
A regular electric adttic fan is 4A or about 480W
Quite a bit of difference.

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