Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login

Site Notices
Posted: 8/14/2007 9:51:52 AM EDT
I was talking to roofer that was giving me a estimate this morning and asked about solar attic fans; he told me that they are crap and will not last past 5 months and the manufactures do not back the product.

I would really like to get a solar attic fan to save some money, but I don't want to get hosed on a bad product.

does anybody else have them? what are your thoughts?
Link Posted: 8/14/2007 9:56:29 AM EDT
I used to have two attic fans, but mine were electric. Kept the attic about 15 degrees cooler mid summer. They didn't use much electricity at all. $250 installed for both.
Link Posted: 8/14/2007 9:58:26 AM EDT
tag
Link Posted: 8/14/2007 9:59:52 AM EDT
Link Posted: 8/14/2007 10:07:35 AM EDT
They run about ~ $300. It consists of a dc motor, a 10 watt solar panel, and a casing. the casing is usually a single molded piece of aluminum.

The DC motor will fail. The warranty is usually for the DC motor. The DC motor has a ~5 warranty. The solar panel has a 25 year warranty. Make sure your roofer installs in where you can access the motor from inside the house. I purchased the replacement motors when I purchased the unit.

My roofer thought is would not work. The roofer thought it had a "cloud sensor" in it due to it slowing down whenever a cloud pass in front of the sun.

I've had three of the units for three years. No failures, they do a good job. No switches to fail, no power bills.
Link Posted: 8/14/2007 10:08:37 AM EDT
Solar cannot provide the power needed without huge solar panels and expense.

Here are the demensions for a solar panel that only produces 145 watts max.
- Dimensions: 43.4 x 46.1x 3.09 inches
- Cost $713

An attic fan I looked up that moves 10,000cfm enough to cool 1400sqft is rated as need 2.8 amps or 336 watts. You would need 3 solar panels that would take up 12 ft by 4 ft of roof space and cost over $2,100.

Link Posted: 8/14/2007 10:09:15 AM EDT

Originally Posted By banthony1:
They run about ~ $300. It consists of a dc motor, a 10 watt solar panel, and a casing. the casing is usually a single molded piece of aluminum.

The DC motor will fail. The warranty is usually for the DC motor. The DC motor has a ~5 warranty. The solar panel has a 25 year warranty. Make sure your roofer installs in where you can access the motor from inside the house. I purchased the replacement motors when I purchased the unit.

My roofer thought is would not work. The roofer thought it had a "cloud sensor" in it due to it slowing down whenever a cloud pass in front of the sun.

I've had three of the units for three years. No failures, they do a good job. No switches to fail, no power bills.


Do you have a link or brand/source for the fans?
Link Posted: 8/14/2007 10:22:05 AM EDT
A quick google search finds this solar attic fan which is very similar to mind. I don't know anything about these folks. Alway looks around for the best deal.

[http://store.altenergystore.com/Lighting-Fans/Solar-Attic-Fans/Natural-Light-Solar-Attic-Fan-10-Watt-Photovoltaic/p816/?source=froogle

1200 square feet, operating at 850 cfms. (No shade trees) If you got shade trees, use a bigger panel. If you don't get a lot of clear sunny days, use a bigger panel.

store.altenergystore.com/Lighting-Fans/Solar-Attic-Fans/Natural-Light-SOLAR-ATTIC-FAN-W-20-Watt-Panel/p2435/

My roof/attic is very simple. Attic Fans are installed on the South side. Additional Vents are installed on the North Side. North Side is a few degrees cooler than the South side. Thus, slightly cooler air is puller into the attic space and hotter air is expelled out via the attic fans. I'm also use more fans than recommended.

If you cannot install the solar attic fan facing directly south, get a bigger solar panel.

Hope that helps.
Link Posted: 8/14/2007 10:27:15 AM EDT

Originally Posted By SWIRE:
Solar cannot provide the power needed without huge solar panels and expense.

Here are the demensions for a solar panel that only produces 145 watts max.
- Dimensions: 43.4 x 46.1x 3.09 inches
- Cost $713

An attic fan I looked up that moves 10,000cfm enough to cool 1400sqft is rated as need 2.8 amps or 336 watts. You would need 3 solar panels that would take up 12 ft by 4 ft of roof space and cost over $2,100.



Wow! 10,000 cfm. You are really moving for some air.

Kyocera KC40 is a 40 watt panel that will give you 2.5 amps. www.solar-electric.com/PDF_files/KC40T-1.pdf It only runs $250.

So is that a 12/24/48 volt app?
Link Posted: 8/14/2007 10:34:36 AM EDT
Or you could have ridge vents installed. No moving parts, best ventillation possible if proper soffit vents are installed.

Link Posted: 8/14/2007 10:42:12 AM EDT

Originally Posted By banthony1:

Originally Posted By SWIRE:
Solar cannot provide the power needed without huge solar panels and expense.

Here are the demensions for a solar panel that only produces 145 watts max.
- Dimensions: 43.4 x 46.1x 3.09 inches
- Cost $713

An attic fan I looked up that moves 10,000cfm enough to cool 1400sqft is rated as need 2.8 amps or 336 watts. You would need 3 solar panels that would take up 12 ft by 4 ft of roof space and cost over $2,100.



Wow! 10,000 cfm. You are really moving for some air.

Kyocera KC40 is a 40 watt panel that will give you 2.5 amps. www.solar-electric.com/PDF_files/KC40T-1.pdf It only runs $250.

So is that a 12/24/48 volt app?


lol, I thought 10,000 seemed way to high. I double checked the specs an they had a typo. It's 1,000 cfm.


I'm looking at the Exterior-Mounted Power Attic Ventilator with Automatic Thermostat
MODEL: RF-49RP.


Air Delivery: 1000 CFM at .03" S.P.
1400 sq. ft. attic floor area.
Dimensions: 9" high, 24" diameter dome ,
25" square flashing plate.
Motor: Shaded Pole type, sleeve bearing,
thermally protected.
Material & Finish: Gray, UV protected, polymeric dome
with glavanized steel flashing plate.
Bird guard is expanded aluminum.
Fan Blade: 4 Fins, 14" diameter, 3" pitch,
aluminum with steel hub.
Thermostat: Adjustable from 50° to 120°F. Preset
to 110°F,
Electrical Rating: 120V, 60 Hz, 2.8A


There is a huge difference between 2.8A at 120v and 2.5A at 12 volts. There is no 12v DC motor that is going to run the attic fan that I listed. The above fan is a "standard" attic ventilation fan. Sure you might find a solar fan that only uses 40watts but don't expect it to operate like the real fans that use over 300 watts.
Link Posted: 8/14/2007 10:51:35 AM EDT
color me interested. my attic needs some ventilation badly.
Link Posted: 8/14/2007 11:02:16 AM EDT
I'm in the process of trying to have one installed, not solar though. Bought the Attic-Aire fan from Lowes, 1500cfm, up to 2100 sq ft. $89, lifetime warranty. Can't get anyone to install it though via my contractor thread. My neighbor up the street has one and I checked it out. Works very well. I went in their attic at 4:30PM last week when temps were over a 100 degrees here and their attic could not have been much over 95. I bet temps in my attic are 140.


Bill3508
Link Posted: 8/14/2007 7:50:06 PM EDT
great replies!
thanks guys, I got a lot of reading to do
Link Posted: 8/14/2007 7:54:09 PM EDT
I've come to the conclusion that most of the heat my A/C sucks out of my house is from attic heat.
Solar sounds nice but I don't see how the regular fans suck that much power to justify solar.
Link Posted: 8/15/2007 11:28:17 AM EDT

Originally Posted By MillerSHO:
I've come to the conclusion that most of the heat my A/C sucks out of my house is from attic heat.
Solar sounds nice but I don't see how the regular fans suck that much power to justify solar.


Windows. Unless you have no insulation in the ceiling.

And unless you have a flat roof, ridge vents beat all fans. Cobra II with snow guards. I have seen them as far north as Wisconsin so they should be fine in most locations.

Just make sure you have soffit vents to match and gone is the need for fans. The Cobras do NOT leak, look much better than any fan and last as long as the roof.
Top Top