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Attic fan versus ridge vent

Posted by avidchef (My Page) on
Mon, Jan 21, 13 at 17:02

Due to Hurricane Sandy we will be replacing our entire roof . Two layers of shingles will be removed. I had planned to install an attic fan, but one of the contractors who gave me an estimate recommended ridge vents. Can anyone
tell me the pros and cons of each option? Thanks.


Follow-Up Postings:

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RE: Attic fan versus ridge vent

do you mean a powered attic ventilator fan?

should be many threads about these on the site,
if you do a site search.

pav's are not recommended because they
pull conditioned air from living space
& ductwork via leakage sites into the attic.
this is how they cool attics.
so, part of the air you pay to heat/cool now
heats/cool off attic.
you pay to mechanically move air,
which occurs naturally
when conditions are right.

cool air in...hot air out.

if you have soffit vents then ridge vents
will work well.
if you don't have soffit vents then
ridge vents won't work

an alternative to pav is to install
passive roof vents.
no motorized parts to replace, no paying
to suck air from house/ducts.

make sure your shingles are for the wind zone
you live in. nailing patterns for high wind
zones should also be used.

best of luck.


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RE: Attic fan versus ridge vent

Powered attic vents will only pull conditioned air from incorrectly fitted and maintained duct systems.
The building code has requirements for attic and subfloor ventilation.
Soffit and eave vents are the standard form these take for attic areas and require baffling to prevent obstruction from insulation.
Powered attic vents are thermostatically controlled and simply accelerate the venting.


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RE: Attic fan versus ridge vent

Ridge vents and vented soffits are the state of the art for attic ventilation if you're doing a vented attic. A lot of places have outlawed the powered vents. Not only because of their role in energy inefficiency, but because of their NOISE. If you are in a wam humid climate, you should reseach an unvented attic. That puts all of your ductwork and other attic stuff in "conditioned" space by putting the insulation against the roof deck. It's more efficient, but it has to be done correctly.


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RE: Attic fan versus ridge vent

A properly installed ridge vent system works constantly with no need for any other assistance. The design moves cooler air from the eaves up through the exit space just under the peak of the roof using physics---how hot air rises.

The attic vent fan adds to your electric bill, is useless when there is a power outage and requires some maintenance.


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RE: Attic fan versus ridge vent

A huge problem with attic fans, is they don't work in the winter.

Around here, I don't know how it passed code, but attic fans were the only ventilation on new builds. The end result is, in the winter, heat rises through the ceilings & insulation, and has no place to go. Thus is condensates in the attic causing severe moisture problems.

One home I was in to look at the problem, was almost like it was raining through the drywall.

My vote is for ridge & soffit vents. There is a formula for intake, which I forget since it's been a good 15 years away from the trades. Quite easy to Google it tho.


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