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whole house fan

post #1 of 14
Thread Starter 

I read some where that in some regions whole house fans are one of the   cost effective ways to cool a home either alone or in conjunction with an A/C. Wanted some input. Also I just ordered a smaller whole house fan that can be easily self installed. The evergreen 1450. Will keep posted on effect.

post #2 of 14

I grew up with whole house fans.  I live in Arkansas, and in the fall and spring, these are great for cooling down the house.  They also work in the summer in the morning or evening.  The key is to only use it when the temperature outside is lower than the temperature inside for the best results.  So late summer evenings when the house is still holding a lot of heat, you turn on your fan and it sucks the colder air in through your open doors and windows. 


I like using them, they can be noisy and they are definitely not for people with bad allergies or people who don't like dust.


These are my observations anyways.

post #3 of 14


Originally Posted by Brian Kanto View Post


I read some where that in some regions whole house fans are one of the   cost effective ways to cool a home either alone or in conjunction with an A/C. Wanted some input. Also I just ordered a smaller whole house fan that can be easily self installed. The evergreen 1450. Will keep posted on effect.


Definitely keep us posted on what you find.  Especially with the warmer months coming up, it'd be good to know.


I found this article on Sillicon Valley Power about installing and using whole house fans.


It says:


A whole house fan is a simple and inexpensive method of cooling a house. The fan draws cool outdoor air inside through open windows and exhausts hot room air through the attic to the outside. The result is excellent ventilation, lower indoor temperatures, and improved evaporative cooling.

  • First cost benefit
  • Equipment cost for whole house fan = $150 - $350
  • Equipment cost for window unit AC = $250 - $750
  • Equipment cost for central AC = $2,000 - $4,000
  • Ventilation
    A whole house fan can be used to change the air in the house and vent odors quickly.
  • Economics of operation
    Operating a properly sixed 2-ton air conditioner with a seasonal energy efficiency ration (SEER) of 10 in Atlanta, Georgia, costs over $250 per cooling season (1,250 hours), based on 8.5¢/kWh, or roughtly 20¢ per hour of runtime. A large 18,000 Btu/h window unit air conditioner with an energy efficiency ration (EER) of 8.8 costs more than 17¢ to operate for one hour. By contrast, a whole house fan has a motoro in the 1/4 to 1/2 hp range, uses 120 to 600 watts, and costs around 1¢ to 5¢ per hour of use.
post #4 of 14

I went to a website that has almost every type of whole house fan on the market. They have installation videos and calculators to help figure out what type of fan is best for the house. I even called them up to ask if there were any drawbacks to any of the whole house or attic fans that I was interested in. I was surprised when they did Not try to sell me on one particular brand ! Rather told me the pros and cons based on their expirience in the field.  I was then able to make the best decision for me. Oh yeah they will even give you a better price than is listed on their website
I saved 40.00 than any published price!
however you have to call them up or email them then ask them for it.
Cheers !

post #5 of 14
Thread Starter 

I installed the fan last weekend. I bought a small one and it definitely cools, it was 15 degrees cooler outside, I ran it for 40 minutes and it cooled the house 6 degrees. It took 25 minutes to cool a whole degree, then rapidly cooled off the house for a total of 6 degrees. It seems that it takes so long to start the cooling due to built up heat in the house. After turning the fan off, it immediately rose 2 degrees , as again I believe it is latent heat in the house walls and furnishings. The total was 4 degrees in 40 minutes at a cost of about 2 cents in electricity. On a spring day in the mid 70s we did not have to turn on the A/C, as we would have had to do for about an hour or 2 due to radiant heat from the sun (newer house, no shade). Bear in mind, this is a very small 1450 cubic feet per minute fan, For max benefit I will need to install a second one down the hall. We only receive one rebate from the utility a year, so I will do this next year. My house is 2500 square feet and this only exchanges the air about every 20 minutes and my attic every 10 minutes ( according to my math, feel free to check it) below recommendations. Even at this, I believe we will decrease A/C use 1-3 hours per day, as we nearly always have cool mornings and hot days with low humidity. Peak A/C cost $2/hr

post #6 of 14

Just an update. This has been the single fastest way I have cut electricity use. I have a small variable speed whole house fan. When I go to bed I open a couple of windows and turn it on high for a Little while to cool the house  a couple of degrees, then I set it on low during the night. When I wake up the house has cooled any where from an addition 4-7 degrees. I close up the house and it takes until about 6 pm to warm up to where my wife even thinks about turning on the air conditioner. Withing a couple of hours, it is cool enough to on the fan again.  My wife has a medical condition where she needs it cool. So, we may run the air conditioner for 20 minutes a day. As apposed to hours last year. My bill just showed a 40% drop from last year and a 25% drop from 2 years ago.  True, we have only been in the mid to upper 80's and things will get warmer, but it will still cut down use of the AC.

     However, it has made assessing the cool-n-save hard to do yet. On the 2 weeks we are well over 100, it will show it's stuff, because it won't get cool enough to run the house fan at night. So a whole house fan can drastically cut the number of months one uses an AC to the hottest ones of the year, July , August beginning of Sept.

post #7 of 14

That's really impressive.  I live in San Francisco and we had some strange unbearably hot weather about two weeks ago (it got to be in the 90s in my apartment).  Luckily we have some back windows and front windows and a long hallway to help move the air through the house once the outside temperatures begin to drop, but perhaps something like that would help speed up the process and not need to be on too long.  And then we would really never need to get an AC unit - which isn't really all that necessary most of the year in SF.

post #8 of 14

The house I lived in with my now ex-husband had a whole house fan and  would never want to own a house again that didn't have one.  In spring and fall I could leave the windows open and turn the fan on low to pull fresh air into the house.  In the warmer weather when the house would get on the hot side during the day but it was still cool out side at night, we could turn on the fan and open windows after dark to cool the house back down to a comfortable temp and never even have to turn on the AC.  I personally loved having it! 


My grandparents have one, as well, and my grandmother likes it.  They don't use it much, though, because my granda hates the loud noise.  I'll admit, on high they are very loud...but both of these fans are old, from 70's and 80's.  If you were to install one in your house now, it would likely be very quiet compared to the technology of yesterday.

post #9 of 14

I'm using this

Attic Aire Whole House Fan

and it works like magic. It's really cool.

post #10 of 14

Same as mjd23 I'm using the attic aire, it's really breezy and I'm liking it each day and I got it from the site that sells it.



post #11 of 14

A variable speed controller, causes excessive motor whine - which creates more noise than is necessary.  The only model that can be used with a variable speed controller is the Evergreen 1450. The other fan motors are not built for a variable speed controller.

Edited by centralcostac - 7/18/10 at 11:58pm
post #12 of 14

As people have been saying, a whole house fan works as long as it is cooler outside than it is inside. Don't leave for work with it running all day thinking it will "ventilate" your house and cool it down, all it is going to do is equalize your home quicker to the outside temperature and make it hotter, blowing hot air around all of that insulation in your home.


The second thing to remember is a bit a building physics. 1 cubic foot of air out of the building through a whole house fan means 1 cubic foot must come in to replace that. Make sure you provide adequate places for the fan to cross ventilate (opening other windows, etc.) If not that you will be sucking air in from less than desirable locations (crawlspaces and attics chaseways, through leaky ducts in those locations, or even worse, backdrafting your water heater (CO poisoning) or fireplace (not that you would have a fire going, but chimney air and soot is not what you want to be bringing into your home.) This is not a good way to ventilate! Create an easier path of resistance to clean outside air.


For whole house ventilation fans that go into the attic, the same rule applies. One CFM out, means one CFM in. You are now creating a situation where you have a positively pressured attic aligned next to a negatively pressured home. And if your attic is leakier (as far as air leaks) to the ceiling than to the outside through the roof, there is a good chance you would be blowing some of that super heated air in your attic right back through your can lights and wall chaseways. Counter productive to what your after (Watched my parents do it to their house for years and wonder why it actually made things hotter.) If your using whole house fans into the attic, make sure you have adequate attic ventilation (roof, gable, soffit vents) to alleviate the pressure you are putting on the attic.


Good luck!

post #13 of 14

I installed three QuietCool Whole House fans in my home in 2005.  My home is in Southern California were it gets pretty hot.  Well my Electric Bills in the summer are very Low.  My bill this month was only $65.00. 


My Neighbor with the same model paid $225.00 since she runs her air every night.  I just come home from work, turn on my fans, and my house get cool quickly. 


The fans have saved me many times the money I spent on them. 

post #14 of 14


Well, this year was very hot so I ran my air a great deal, but the two years previous were perfect for a whole house fan.  Interestingly I didn't have a whole house fan so I improvised.  I had a large window fan that wouldn't fit in my window so I placed it above my craw space blowing air downward.  Since the craw space vents were small, I had to limit the fan to the lowest two settings, but it made a huge difference.  I would let it run all night and by morning, it was almost too cool in the house.  I would then close my windows and the house would stay cool for most of the day.  By the time the temperature in the house started getting warm, it started to cool down outside and I would repeat the procedure.  I rarely ran my air those two years and I was always cool.   


I just installed a whole house fan from QuietCool (QC-2250) and am very pleased with it.  The most important thing about this particular fan is that it's fairly quiet and pulls a great deal more air in the house compared to my window fan that I had been using.  Being quiet is very important.  I know many people with whole house fans that don't use them because of the noise issue.  Many sound like a helicopter landing on your roof.  A larger fan will cool your house more quickly, but a smaller fan will keep cooling your house through the night with less energy usage.  As one poster mentioned, his fan would cool the house quickly, but when he turned it off, the house would heat up again from the ambient heat of the walls and such.  It's a matter of choice, but the best option would be a fan with adjustable speeds, one to cool the house quickly and one to keep pulling air at a lower power usage.  Keep in mind that if the fan is too loud, you will not use it very often.


It used to upset me that, even with the air running, sometimes I would walk outside and it would be much cooler than inside.  Also it didn't make any sense that my air would have to keep running when it was very cool outside.  This brings us to the other thing that a whole house fan does.  By pulling the outside air into your house and blowing it into your attic, it removes the heat stored in the insulation from the sun during the day and helps your house stay cooler longer during the next day.


Anyway, in time, the fan will pay for itself and having fresh air in your home is a real pleasure.           

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