Whole house fans, what do I need to know.


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Old 06-05-05, 08:34 PM
toddmd2
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Whole house fans, what do I need to know.

My house is around 1600 sq ft and the second story is getting nice and toasty at night. I'd like to install a whole house fan to help keep the upstairs cooler at night without having to run the ac all evening. What size do I need? Are they hard to install/wire? Is there any other info I need to know going into this?
 
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Old 06-07-05, 07:44 PM
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Whole-house fans are an excellent choice if your nights are cool, and I'm surprised more people don't install them. Your house is 1600 sq ft, x 8' ceilings = 12,800 Cubic feet. It is recommended to completely change the air every two to three minutes, which indicates you need a fan with approx 5,000 CFM. A 30" fan would suffice for your application. I prefer belt-driven fans to direct drive, because they run slower and tend to be quieter. Try to find a fan with two speeds (most are) so you can cool a hot house down fast, then switch to low to maintain a gentle breeze. Most models are not particularly hard to install if you are handy. Some fans are designed so you don't have to cut a joist to install them, while others require you to do some structural framing work in the attic. You must ensure that your attic has enough sq feet of venting to handle the air from the fan to the outside.
Some Whole-house fan brands are Broan, Certainteed, and if you are authorized to buy at Grainger there is Dayton. They are very good fans by the way.
Good luck!
 
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Old 06-08-05, 11:21 AM
toddmd2
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Originally Posted by Andrew
Some fans are designed so you don't have to cut a joist to install them.
When you are referring to the above, are you talking about standard circular whole house fans? All of the circular models I've found require framing. All of the models I've found that require no framing are often hundreds of dollars more than their counterparts. Such as this one:

http://www.wholehousefan.com/theghost.html

You also mention that I need to know how many sq ft of venting I have available in the attic. How much is adequate? I have two vents near the peak of the roof on either side of the house (what size they are I'm not sure). What is the recommended sq footage?
 
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Old 06-08-05, 11:48 AM
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. I'd like to install a whole house fan to help keep the upstairs cooler at night without having to run the ac all evening
Ill put it this way dont do it or think about it .A vent fan on a tstat for just the attic do it .But for the whole home dont .You dont want all that moist air in the home. When you turn the AC on it take like 5 to 6 days for it to just get started to get all the hunidity out of the home. This is what makes you feel cool. Not just a temp drop in the home. If you put this fan in ,there is no way that the AC can run all day and make you feel cool. Try with the blowe on 24/7 and see if that helps.
For just the attic you should have 1 sq ft for every 150sqft in the attic 1/2 of this should be in and 1/2 of it out
ED
 
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Old 06-08-05, 12:12 PM
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Many whole house fans do not require you to cut a joist to install it on the attic floor. These are actually some of the LEAST expensive fans. I've never heard of the one you link to.
Remember, whatever air you put into the attic from your fan has to go outside. Measure the size of your existing vents. you want at least the same area as the area of your fan blade.
 
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Old 06-08-05, 04:53 PM
toddmd2
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Thanks for the advice Ed, but I still think I'd like the whole house fan. I grew up with one and I like the airflow they create.
 
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Old 06-08-05, 05:03 PM
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Dont know where you are but if you want to go that way go for a Evaporative cooler then blow the air in .

ED
 
 

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