Whole house fan for cathedral ceiling?

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Old 10-09-08, 03:51 PM
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Whole house fan for cathedral ceiling?

Hello all,

I would like to add a whole-house fan for my two-story house. The second story has a cathedral ceiling, which is the underside of the roof. I can't use traditional axial whole-house fans, since they are meant to blow into an attic, and I have no attic.

I've looked around, and it seems there is no off-the-shelf solution here?

The only idea I can think of is to have the fan vent out the gable, and build a "box" under the peak of the ceiling to support and enclose it. A centrifugal fan would seem to work well here, since it would pull air up from the bottom and push it out the side.

Has anyone tried this before? Where did you get your fan? What CFM did you use for what size house? Did you manage to find any self-closing louvers like for a traditional whole-house fan, and where did you buy them? How about insulation and closing off the fan intake during cold weather?

Alternatively, are there completely different solutions out there I should consider?

Thanks for any responses and/or ideas.
 
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Old 10-19-08, 05:22 PM
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I second this question

I have the same issue. It gets very hot on my 3rd floor w/ cathedral ceilings. I know it would be much more efficient if there was an exhaust fan installed to blow out the hot air once in a while. They don't seem to make fans for this...
 
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Old 10-20-08, 08:42 AM
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A whole house fan needs a lot of vents to exhaust the air. So you need to provide plenty of space for the air to go after the fan pulls it out of the house.

I would also be concerned about mounting a fan at an angle for a motor that is designed to have a vertical shaft. The angle may impose unplanned load on the motor.

Not everybody does this, but I go up in the attic every fall and insulate between the fan blades and the louvers. if you don't, you'll lose a lot of your winter heat. So you should plan for that. Some manufacturers do sell insulated louvers.

I've just thrown out a few thoughts, but, as you can tell, I have no real solution for you. The only solution might be to find another place for your fan--a place where there is a horizontal ceiling and an attic above.
 
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Old 10-20-08, 09:24 AM
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Problem is that we have cathedral ceilings without attics. We are looking for a solution to vent out the hot air that accumulates in our upstairs rooms during the warm months.

my prolem is that my downstairs is always cool and my upstairs is always warm; which goes to the extremes during the summer/winter. It gets HOT on my 3rd floor cathedral ceiling room in the summer and COLD in my kitchen (1st floor) in the winter. I do reverse the vents but that doesn't help much.
 
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Old 10-20-08, 10:42 AM
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The whole house fan won't help with your cold winter kitchen.

Perhaps you just need one or more simple ceiling fans to circulate the air. This will help keep the kitchen warmer in winter. If you have air conditioning in the summer, it will also help to keep the upstairs cooler in the summer. Even without air conditioning, it will at least even things out a bit.

Some people also like to leave the fan on their central furnace/AC in the "on" position rather than the "auto" position to help even out the temperatures.
 
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Old 10-20-08, 12:35 PM
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Originally Posted by John Nelson View Post
A whole house fan needs a lot of vents to exhaust the air. So you need to provide plenty of space for the air to go after the fan pulls it out of the house.

I would also be concerned about mounting a fan at an angle for a motor that is designed to have a vertical shaft. The angle may impose unplanned load on the motor.

Not everybody does this, but I go up in the attic every fall and insulate between the fan blades and the louvers. if you don't, you'll lose a lot of your winter heat. So you should plan for that. Some manufacturers do sell insulated louvers.

I've just thrown out a few thoughts, but, as you can tell, I have no real solution for you. The only solution might be to find another place for your fan--a place where there is a horizontal ceiling and an attic above.

I was thinking of using a centrifugal fan, like the ones that are in furnace blowers. These are designed to propel air at a 90 degree angle from the intake. They supposedly move more air for a given amount of electricity as well. If I duct the outgoing air directly outside, shouldn't this solve the problems?
 
 

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