Will Whole House Attic Fan fit through fan opening?


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Old 07-06-14, 10:10 AM
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Will Whole House Attic Fan fit through fan opening?

I am thinking of installing a 30" whole house attic fan but my entry hole to the attic isn't large enough to pass the fan through. The actual width is 34 inches. Will the opening I have to cut in the ceiling be large enough to lift the fan through to the attic?

Also, I have room to elevate the fan above the ceiling joists using 2x10's or larger. Will this make the fan quieter or will a tunnel effect make it louder?
 
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Old 07-06-14, 01:05 PM
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Will the opening I have to cut in the ceiling be large enough to lift the fan through to the attic?
I wouldn't think so. ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,
 
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Old 07-06-14, 01:34 PM
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There should always be access to the attic, fire department or just repairs. You need another opening.

There are also issues with whole house fans, especially if you have any combustion appliances, gas hot water, gas heaters, fireplace, or furnace. The fans are typically so powerful that when operating they will defeat (backdraft) most chimneys. Large range hoods have the same warning.

Bud
 
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Old 07-06-14, 02:24 PM
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If all you cut is a 30" square hole, the diagonal length between 2 corners will be 42". I think it will probably fit...or they wouldn't sell very many of them.
 
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Old 07-06-14, 02:55 PM
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The problem is that there is a ceiling joist in the way. The fan basically sits on top of three ceiling joists.
 
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Old 07-06-14, 03:06 PM
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Normally you have to cut a joist and box in around it. At least every fan I ever saw was like that. Like I said, if it weren't possible, they wouldn't sell very many unless they house was originally built for one, and not that many are.
 
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Old 07-06-14, 03:45 PM
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Looks like I may have to cut out that center joist to make this work.

I am still wondering if elevating the fan 10-12 inches will make the sound less obtrusive?
 
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Old 07-06-14, 04:02 PM
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I doubt it, any vibration will still be transmitted through the structure. Depending on mounting method (most just screw down to a box made out of wood I think), putting some heavy rubber or dense foam (maybe even a set up bead of spray foam?) between the fan and wood would help with that.

Actual fan/air noise...doubt there's much you can do except buy a very low noise rated fan. Not as cheap as the typical Big Box fans though.

Don't forget you'll need a insulated box to cover it in the winter.
 
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Old 07-06-14, 04:52 PM
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Didn't see mentioned, are your ceiling joists part of trusses?

Bud
 
 

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