Author Topic: Those attic turbine fan vent things  (Read 2349 times)

puglogic

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Those attic turbine fan vent things
« on: December 27, 2013, 12:35:43 PM »
Thricesplice's post got me thinking again, as we're going through a similar phase of paying a lot of attention to the attic.

Like a lot of houses, we have those attic turbine fans that spin and help ventilate the attic.  We also have soffit vents.  And there's a lot of air turnover in our home, according to a recent energy audit.  She came just short of sentencing me to a week in the attic with 20 tubes of spray foam sealer, and don't come down 'til you're done  ;)

My question to you home improvement folk is one that is somewhat contentious on the web:  Those turbines spin like mad all winter in our cold climate (Colorado at 7500 ft).  If we were to put a cover on them for the winter, would the soffit vents provide adequate ventilation to avoid the downside of poor attic air circulation?  Would it gain us anything at all to cover them? (has anyone ever done it?)     It just seems like we're blowing a lot of air out, but that could just be a kneejerk reaction on my part.

paddedhat

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Re: Those attic turbine fan vent things
« Reply #1 on: December 28, 2013, 06:24:07 AM »
As a builder in a much milder climate (2000' 40-60" snow annually) I wouldn't see the point of allowing the thing to create negative pressure in a cold environment. If the roof is fully vented otherwise, as in full soffit and ridge vents, then the only purpose of the turbine is to cool the space by venting excess heat. If the house is inadequately insulated, and the roof is poorly vented, then the turbine might be instrumental in preventing ice dams and needs to be in operation to prevent damage. Obviously, that would be a little tough to determine without a visual inspection.  Personally, I would carve a nice foam plug for the underside of the turbine,plug it,  and let it rest for the winter, while being very vigilant as to how it affects the performance of the ventilation. I would hope that any online battles you read of regarding this issue are limited to controlling ice damming, as the thing is undoubtedly contributing greatly to negative pressurization and the "chimney effect" and sucking pretty hard on your wallet on these nasty winter days. Good luck