Attic Fan or Turbine vents??

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  #1  
Old 04-23-08, 07:23 AM
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Question Attic Fan or Turbine vents??

My mom lives in a small condo community that's fairly new. (2-3yrs). These are ranch condos 3 units per building with firewalls in-between each unit.
When she moved in, one of the builder's handymen installed an attic fan for her as did a few other residents based on some inspector's suggestions and feedback from friends. It gets really hot in the attic during Georgia summers and it's set on a thermostat and really seemed to help her cooling bills last summer.
Anyway, long story short--at the last HOA meeting, one of her follow residents said he had a roofing friend suggest the community spend the money to install "vents" in each building (2 per I believe) that run on turbines? (I'm not too technical but I think that was the term). He said, his friend told him attic fans are worthless and do more damage to a roof and reduces the life expectancy, than these vents. That you can't run both. It's either one or the other. Well, naturally the few folks who had attic fans installed like my mom are not happy and feel this "friend" is wrong about these vents. I would appreciate any input about one versus the other. Growing up, we had attic fans and I never recall my family having any roof issues.
Any thoughts?? thanks!!
 
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Old 04-23-08, 08:37 AM
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Interesting- I take it you now don't have turbines, just the attic fans. You would probably benefit more with the wind driven turbines than the attic fans. It is costing you to run the attic fans.
My experience with the attic fan, usually 1500 cfms, is that they don't stay ahead of the heat production during full sun and only help in late afternoon. You can do a test- put a remote thermometer in the attic and see just what the temp is with the attic fan working(I have one of those battery units with a 10' lead that I can read in the house). If the current temp is OK with you, then don't do the turbines. I prefer the turbines.
Here in Calif. it is common to have the turbines and an attic fan. The combo will help. What I found the best, is to turn that attic fan around and blow into the attic, that will help the hot air to vent through the turbines, expecially on quiet days.
It seems to me that if you have adequate insulation, R-30 min, and at least 2" of insulation wrap around your ducts, it won't matter that much whether you reduce it more or not.
 

Last edited by rpatzer; 04-23-08 at 10:19 AM.
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Old 04-23-08, 10:36 AM
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Don't agree! The fan is the only way to go. It will move more air. Also very bad advice to put the attic in a positive pressure. It could force the heat plus insulation down into the home and cause bigger IAQ problems.
 
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Old 05-18-08, 07:06 PM
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I too... vote for the electric fans. When little or no winds the
turbines don't work to good.
 
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Old 05-19-08, 02:27 PM
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Here we go again. Sorry Airman. Although the electric fans do a good job, their lifespan is too short. Motors burn out at a horrendous rate. I replaced the ones in my mother's house every year, it seemed. I retrofitted with turbines and no problems with heat since.
And Are343, you don't need wind to operate the turbines, as they work on the convected heat in the attic itself, drawing cooler air from the eave vents. Just two more cents worth, no change required.
 
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Old 05-19-08, 03:37 PM
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I live in the NE so I don't have a problem with attic temps. I am curious though, if the turbines work well by convection alone, how are they any different than a normal soffit, ridge and gable vent combination?

Epirate - I suggest your mom and her fellow attic fan friends get an evaluation from a pro before scrapping their fans and paying for turbines.
 
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Old 05-19-08, 04:15 PM
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Heres the question I have about the turbines. All they have is the spinning vanes, they don't drive a fan or blades in the interior (at least the ones I know of), so how do they move any more air than a comparably sized roof vent? I understand how a gas or steam turbine works, and I don't see it with the windbirds.

And if its a day w/o wind (doesn't happen much here...lol), don't the vanes actually restrict some of the flow by converting it to rotational energy?
 
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Old 05-19-08, 04:23 PM
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Late entry in this discussion, but I vote with Chandler. But use only "Whirley Bird" vents, they seem to last forever. They require no power or power connections, which can be expensive to install and run. And other comments notwithstanding, they do move air even when there is no air moving. If they are turning, which they do even in dead air, there is air moving. And properly mounted high up in the attic, they provide a hole for the super heated air to escape.
 
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Old 05-19-08, 05:51 PM
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Justbill - I'm with Gunguy. If windvanes are moving without wind it is because of convective currents. The very same currents that move air out of a conventional ridge or gable end vent. It seems like in the case of no wind, the turbine vanes are actually an impediment to air flow. They may indicate flow by turning, but they aren't aiding it.
 
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Old 05-19-08, 06:40 PM
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Yall would not bring up this topic from the past would you! MY Friend (Chandler) I will agree that the motors don't last very long, but they are less than 40 bucks last time I purchased one. I get about 4 to 5 years out of them, and if I oiled them like I should I would get more. One year you must have had a bad one. I'll just close with this. The power vents will move more air than the turbine, and with non sealed attics airflow is the name of the game.
 
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Old 05-19-08, 07:47 PM
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And concurring with some of the others, a continuous ridge vent would work well, too, but I was going on the fact there are already holes in the roof. Passive is the way to go, although I will agree ( I hate doing this) with Airman, fans do move more air per capita. I just don't like the fact there is something to break. Hot attics and wet basements are my two least favorite places to work.
 
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Old 05-19-08, 10:11 PM
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Another thing I like about the electric fan is the look. They
are low profile , unlike the turbines to me which give the
house a factory look. The turbines also have their problems
like freezing up or squeaking when not maintained properly. Both
electric and turbines have their pro's and con.
I got about 3 1/2 years out of the original motor before it
failed. Took me about 30 minutes to change out motor , all work
was done in the attic. No roof work involved.
 
 

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