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Old 12-01-2008, 05:55 PM
 
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Before i buy one, im curious to know if they are reliable and a good investment for $400 plus . ? Is the solar cell panel durable ? Any opinions ?? Thanks.
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Old 12-01-2008, 06:05 PM
 
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Out of curiosity, why would anybody spend that kind of money on that kind of thing?

I've used a lot of these stationary, and turbine, vents and have always been quite satisfied.

http://www.lowes.com/lowes/lkn?actio...f+vent+turbine



Is there something else you're wanting the attic fan to do?
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Old 12-01-2008, 06:32 PM
 
464 posts, read 1,524,636 times
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Quote:
Originally Posted by JeffreySH View Post
Out of curiosity, why would anybody spend that kind of money on that kind of thing?

I've used a lot of these stationary, and turbine, vents and have always been quite satisfied.

http://www.lowes.com/lowes/lkn?actio...f+vent+turbine



Is there something else you're wanting the attic fan to do?
To get rid of the heat buildup in an attic on hot days, you need a power attic fan. Stationary vents/turbines/ridge vents are virtually useless. Go in your attic on a 90 f day and youll see what i mean. The benefit to a solar powered attic fan is there is absolutely no operating cost ; in a sunbelt state like Florida, I estimate the payback time being approx. 2 summers versus a 115 v. attic fan.
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Old 12-01-2008, 07:12 PM
 
695 posts, read 1,202,455 times
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Quote:
Originally Posted by HowDeDo View Post
To get rid of the heat buildup in an attic on hot days, you need a power attic fan. Stationary vents/turbines/ridge vents are virtually useless. Go in your attic on a 90 f day and youll see what i mean. The benefit to a solar powered attic fan is there is absolutely no operating cost ; in a sunbelt state like Florida, I estimate the payback time being approx. 2 summers versus a 115 v. attic fan.
Okay, that makes sense. I don't live in the sunbelt.

That said, have you ever seen one of those wind turbine vents work? If there is ANY breeze, they're spinning. Even without the turbine, it is the nature of heat to rise. So if there are vents in the peak, the heat will naturally disperse.

I'm also assuming you're fully aware of the necessity of soffit or eave vents for proper air intake, right?



Good luck!
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Old 12-01-2008, 08:17 PM
 
Location: Raleigh
542 posts, read 1,367,381 times
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I have my own opinion of attic fans, but I'd rather source a true expert (and legend) in the building sciences.

Advanced Energy

I strongly recommend reading the entire article, but here is a quote from the end:

What happens if we have a powerful exhaust fan running in the attic? While the diagrams that come with the fans always show them pulling the air in through the soffit vents or gable-end vents at the other end of the attic, the fact is that the air didn't go to the same schools as the people who drew the diagrams. So, when the fan comes on, it pulls air through the light fixtures, around the attic stairway, and through any other holes available.
The attic is, in fact, cooled by your air-conditioner. And while that attic fan is pulling air out of the house, it is also pulling make-up air into the house from outside or from the crawl space. Some of these attic fans are powerful enough to create a negative pressure in the house. If you have a gas water heater, this negative pressure can cause it to back-draft, putting poisonous combustion gasses into your house instead of up the flue.
The bottom line? Code-required attic ventilation levels are adequate. Putting in extra ventilation is probably a waste of money. Finally, powered attic vent fans are more likely to increase energy bills than to reduce them, and they can create dangerous conditions in your house. A little extra money to really seal the ceiling from the attic will go a long way toward providing comfort and lower bills.
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Old 12-02-2008, 06:24 AM
 
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Im an HVAC Tech and ive installed loads of 115 v. powered attic fans in homes. They work extremely well providing theres enough makeup -air perforated soffit panels or gable intake grilles. If you dont exhaust the attic , the superheated air will infiltrate thru the ceilings and make the house much warmer. Ive seen Turbine fans spin but they do not move anywhere near the amount of cfm airflow needed to exhaust an attic properly . A solar powered attic fan will move up to 850 cfm airflow with adequate makeup air which is approx. the same amount of air that a typical house furnace blower does. I just need to know if they are reliable and what their longevity is ; I dont want to be replacing it every 4 or 5 years.
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Old 12-02-2008, 10:02 AM
 
Location: Vermont
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If it is 110 F outside, and you have 2 large gaping holes (windows) in the attic and it's 90 F outside, it's going to pull the air from outside. Path of least resistance.
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Old 12-02-2008, 10:57 AM
 
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Quote:
Originally Posted by joe moving View Post
If it is 110 F outside, and you have 2 large gaping holes (windows) in the attic and it's 90 F outside, it's going to pull the air from outside. Path of least resistance.
Not many attics have windows in them...unless its a converted room up there. And even so, the attic will always be hotter than the outside air is .
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Old 12-02-2008, 06:45 PM
 
Location: Raleigh
542 posts, read 1,367,381 times
Reputation: 760
Quote:
Originally Posted by HowDeDo View Post
Im an HVAC Tech and ive installed loads of 115 v. powered attic fans in homes. They work extremely well providing theres enough makeup -air perforated soffit panels or gable intake grilles. If you dont exhaust the attic , the superheated air will infiltrate thru the ceilings and make the house much warmer. Ive seen Turbine fans spin but they do not move anywhere near the amount of cfm airflow needed to exhaust an attic properly . A solar powered attic fan will move up to 850 cfm airflow with adequate makeup air which is approx. the same amount of air that a typical house furnace blower does. I just need to know if they are reliable and what their longevity is ; I dont want to be replacing it every 4 or 5 years.
Did you actually read the article? The author of the linked article has studied the performance of buildings, including the effectiveness of attic fans for many years and has come to the educated conclusion based on tests and actual building diagnostics that they are absolutely unnecessary and the use of an attic fan will result in more power consumption, not less.

Mike
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Old 12-03-2008, 05:35 AM
 
464 posts, read 1,524,636 times
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Quote:
Originally Posted by MikeNC29 View Post
Did you actually read the article? The author of the linked article has studied the performance of buildings, including the effectiveness of attic fans for many years and has come to the educated conclusion based on tests and actual building diagnostics that they are absolutely unnecessary and the use of an attic fan will result in more power consumption, not less.

Mike
I read the text highlight you posted ; as an HVAC Tech whos installed a few dozen 115 v. attic fans that have adequate makeup air soffit grilles/panels , the Homeowners all comment how much comfortable it is on their upper floors. Further, an attic fan will actually reduce the cooling load on the house making it run less because less heat is penetrating in thru the ceiling , thereby making the a/c run less and at least offsetting the power required to run the attic fan . The Author of the article is assuming inadequate makeup air from soffit grilles in his analysis but this can be easily remedied by adding more soffit grilles and/or roof static intakes to accomodate the amount of air being exhausted . Lastly, another benefit of an attic fan is increased longevity of the roof deck from reducing the temperature of it. A google search will substantiate my assertions.
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