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JLAMBERTI 06-20-2012 01:50 PM

an attic fan AS a whole house fan?
From my research an attic fan pushes air out of attic and and draws air in from outside to exchange air in the attic, no exchange with the living space. A whole house fan pushes air from the living space into the attic and forces the attic air out through the soffit vents.

My problem is that I have a post and beam style A-frame house. My attic space is about 150 sq ft of my 1200sqft. It is roughly centered and does not have soffit vents or even the access to put them in (only one side is an exterior wall).

Whole house fans are spec'd for attics greater than 500 sq ft and need lots of exterior venting (I have none)

Question: Can I do a traditional installation of a attic fan (1600 cfm) under my gable then cut a vent between my attic and living space to allow the hot house air be drawn into the attic and eventually out? How big should that vent be?

Thank you much.

Marty S. 06-20-2012 04:52 PM

What's the plan to keep outside air and hot attic air from coming into the house when the fan is off? A simple gravity damper isn't going to do it. IMO cutting a huge hole in the building envelope is a baaaaad idea but we'll see what others have to say.

JLAMBERTI 06-21-2012 02:04 AM

attic fan as a whole house fan
Thanks for the reply Marty.

The gable vent is gravity damper building exterior. The fan is to be mounted right against it and it's designed to open and close so I don't know what problem to look for. As for the interior vents I would use common 10x6 registers but in reverse. In winter I plan to use the louver to close them and maybe a magnetic cover as well.

You bring up an interesting point. If on a 90 deg day the house with open windows gets to 90 and the attic with no vents say gets over 100; punching a hole between my attic and the living space will let the 100 deg air into my house. I would then have to rely on my fan to depressurize the attic and keep that hot air from flowing into my house. hmmm. Power interior vents?

These are the parts I was going to use.



