Whole House Fan, Are They Worth it?

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  #1  
Old 08-03-04, 02:35 PM
bfreeman15
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Whole House Fan, Are They Worth it?

I live in Temecula, CA just north and inland from San Diego. I gets pretty warm here in the summer, average 90+. I am buying a new home, but it does not have a whole house fan system included. The system sounds interesting, but do not have a lot of information. Some of the questions I have about the whole house fan system:

Are they worth the time and expense?
Are they quite?
How difficult would this be to add after we move in?
Can anybody recomend a reliable and cost effective brand?
Is this a project I could do myself over a weekend?
How big of a unit do I need for a 2 story 2100 sqft house?
 
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  #2  
Old 08-03-04, 03:47 PM
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Hello; bfreeman15

Familar with the area in which you live. Very HOT in summer months.

Would not recommend a whole house fan. Having one requires windows to be opened so outside air can enter and be blown into attic and out the louver vents & gable vents, etc. (whichever applies)

Such a system draws in the hot outside air along with any dust in the air. Thus not really cooling the air, just helps to keep it in motion. also draws in dust which settles everywhere.

Will help to cool attic space some but not enough to offset the downsides of a whole house ventilation system.

What would be better in a new home is an attic ventilation fan. This system does not draw in air throught the entire house. Rather only into the attic throught the lovers and gable vents and blows the air out the fan.

Thus helping to reduce the attics air temp by circulation of the air. (Keeping the air moving) Plus, the attic will be insulated to help prevent the attic heat from passing into the ceilings and into the house.

Any attic ventilation fan can and will help lower cooling (Air Conditioning) costs even with air insulation. Does get well over 100 to 120 plus degrees in attics in your area. Attic ventilation fan will be helpful. Have one installed with an automatic on/off temp switch which will control temps.

"My Two Cents"
 
  #3  
Old 08-05-04, 12:01 PM
bfreeman15
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Attic Fans

Thank you for the reply. Do all attice fans attach to the roof? Are there any alternatives that might attach to existing vents?
 
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Old 08-09-04, 03:17 PM
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Check out Home depot and lowes they both have attic roof vent fans that will go on the roof and also fans that will mount on the gable vents in the home.If you even think AC you dont want a whole house fan

ED
 
  #5  
Old 02-11-07, 10:47 AM
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yes!

I disagree with the previous post. I live in so california and it is indeed hot BUT the evenings tend to get cooler. I turn on my whole house fan in the evening for a bit and it pulls in the cool air from outside and cools the house. THATS WHAT ITS SUPPOSED TO DO. So go ahead an install one -- trust me it will work great!

The zhotman has spoken!
 
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Old 02-11-07, 11:37 AM
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My dad has one in his north texas home and it works wonderfully in spring and fall and cooler summer days when it's not quite hot enough to turn on the AC but too warm to sleep comfortably. He opens the windows in the cool basement and turns that thing on and the breeze it creates is amazing, and wonderful. So as long as your house is designed in such a way that you can suck cool air from somewhere else, I like them. The one he has is ancient and very loud, but it will completely exchange the air in the house in about 10-15 minutes.
 
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Old 02-11-07, 12:13 PM
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The fans feel ok. BUT they do pull in all that humidity in the home . So if you think you have and need AC in a day or two . It will take the poor AC the next 5 days to just try and dry out the home . So you feel cool in it
 
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Old 02-11-07, 06:27 PM
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We took out the one a previous owner had installed in our Atlanta home. There was rarely a time when we wanted to pull that much outside air because of the humidity and pollen that is frequent in our climate.

We took it out because it was so darn ugly in the hallway ceiling, it was a big heat/ac loss, and it sounded like an airplane when it was running.
 
  #9  
Old 02-12-07, 02:37 PM
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We have one in our home in NW Ohio. We only run it for about 15 min in the early morn and in the evening after the sun starts to go down. IT helps keep the house cool in during the morning hours and helps to cool the house down quickly for the evening and night time. Ours is located above the landing on our stair case, directly at the bottom of the stairs is the front door. During the day if it is very sunny and the attic is heating up, we can open the front door and turn the fan on low for a little while and the fan draws almost all of the air from outside up the stairs and into the attic, with out losing the coditioned air inside(except for the stair case). we have seen a drastic decrease in our cooling bills. The fan is belt driven it is a little noisy on high when in the vacinty, but on low it is barley noticeable in the house.

Also, there is a trick to finding out what windows and how much to open each in order to get the best and coolest air flow.

We have not noticed a large increase in dust, but spring pollen sometimes is a problem.
 
  #10  
Old 03-16-08, 05:06 PM
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Attic whole-house fan

When I lived in San Diego, I had an attic fan installed. It worked beautifully, but not the way the contractor installed it; it was too noisy 'til I modified the installation.

The 30" 1/3 HP 2-speed belt driven fan was installed in a gable. The motor noise could be heard throughout the house. After considerable experimentation, I was able to make it so quiet that it was totally inaudible from any place in the house on low speed, and barely audible on high speed from some places in the house.

To isolate the noise, I ended up making a wooden frame a bit larger than the fan (about 1/2" between the fan and frame on top, bottom, and sides) using 2 x 6" instead of 2 x 4", so the fan could swing in and out a bit without hitting anthing, and suspending the fan from springs. Noise also traveled through the Romex connecting the motor, so I replaced that with very flexible 4 wire cord with a weight ( considting of a 2" threaded pipe nipple with a cap on each end) in the middle of the run. I suspended the weight from a rafter using nylon cord, and used nylon cord to tie the weight to the 4 wire cord. I also found it necessary to use rubber mounts to mount the motor to the fan, even though the motor had built-in rubber mounts. Having the belt too tight also resulted in noise. The result: Total inaudability on low speed, and very quiet on high speed.

The ceiling shutter and shutter through the gable did not work well (they would not open fully on high speed, and the ceiling shutter would not open at all on low speed), so I motorized them. However, the standard shutter motor installation permitted shutter motor noise to be transmitted, so I ended up suspending the shutter motors on springs and connected the motor arms to the shutters with more springs. The result: The shutter motors were inaudible.

I also installed a 24 V thermostat, using relays and a transformer to operate the fan. The result: The fan quietly cycled as the thermostat turned it on and off. I used a manual 2-speed switch and 12 hour timer also.

I also ended up installing a 2nd ceiling shutter so that one of the bedrooms could be ventilated with the door closed.

By the time I finished with all that, the fan worked beautifully and kept the house comfortable at night; I did not have air conditioning.

Now that I have explained how to install a whole-house fan so that it is really quiet, others can do it without all the experimentation.
 
  #11  
Old 03-16-08, 06:34 PM
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If you put in a stock attic fan, it usually doesn't do much good during peak heat because it can't pull out heat as fast as it is being produced by the sun. Towards evening, it will be of benefit to the attic. BUT, if you have adequate insulation in the attic it won't make a bit of difference to the area below. It will benefit the AC ducts.

What I have done with ours, Lakewood CA, is to put a 20" fan in the crawl space to the attic in the hall way and turn it on at night. It is quiet enough on low and will pull in cool air from whereever you have an open window. I also put a trap door so I can close it during the day.

Another idea is to put your 20" fan in a window away from the bedrooms, again installed so you can close the window during the day, and also let it exhaust the whole house during the evening.

This size fan is not as efficient or fast as your whole house fan, but it works after the evening has cooled down.

If you wanted to do an attic fan, I would suggest a Patton type size, 18" fan with 4500 -10,000 cfms and on low or medium, blowing it into the attic, it will slightly pressurize the attic and it will blow the hot air out where ever there is an opening. It will also circulate the attic air more causing it you not "cook" like dead air. If you suck out, it will draw from the closest and easiest opening and leave your space the fartherest from the fan the least exhausted. In testing temps, in and out, I found that blowing in will cool the attic better, by several degrees.
I believe most stock attic fans are basically 1500 cfms. I think that is too small for a single story. Yours is a 2 story with probably 1300 sqft/level. That means your attic space is smaller and the smaller fan would probably work for you. Just some ideas.

We have AC in Lakewood, but only use it 2-3 weeks during peak heat. Otherwise, that exhause fan in the den pulls a nice breeze when we sleep, and we don't hear it. Or, you could mount a bigger fan in the garage, leave that door open at night and leave the fan on high. Just some ideas. Good luck.
 
  #12  
Old 03-21-08, 09:26 AM
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Whole House Fans - The Truth

If you want to use a Whole House Fan - look at one with doors to keep weather out during hot or cold times. Also, you will only run the fan once weather outside is cooler than inside. In cooler areas this will allow you to not run the A/C as offten or not in all in some cases for our home.

I would look at these sites for fans and more info:

http://www.wholehousefansdirect.com/...eFansBegin.asp

and
http://www.tamtech.com/

Let me know if anybody needs more info
 
  #13  
Old 04-08-08, 05:07 PM
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Easy to Install and Plenty to Choose From

My wife and I are not the most handy, but we purchased a whole house fan last summer and were able to install it in an afternoon. I had to have my dad help me with the wiring though. For the wiring, the fans just plugged into a regular outlet (in the attic). But the catch was, that outlet needs to be controlled by a switch. So we had to hook up a switch in the hall to power the regular outlet in the attic (which we had to install as well)

We purchased the Quiet Giant from Quiet Cool http://www.atrendyhome.com/silent-giant-fan.html. It's very quiet and pushes 4500CFM. It's quieter than a box fan.

The vent sits right between the ceiling joists (ours just barely fit) but the fans hang from the rafters in the attic so the fans aren't rattling the joists and the noise isn't right against the vent.

It creates an awesome breeze all thruout the house, and keeps the house temp close to the outside temp. I don't think it ever brought the inside temp exactly to the outside temp, but it was usually within a couple degrees.

You only use it in the morning and late evening hours, then you turn it off and close the windows and doors to keep it cool. Hopefully, you get the house cooled down enough that as it gradually gets hotter outside, the house doesn't get too hot inside. And by the time it does get pretty hot inside, the temperature outside is starting to cool off again and you can turn the WHF back on again.

Alot of the sites have a calculator that shows how much CFM you need based on how much square footage your home is. We have a 4000 square foot home and the 4500CFM works great. I think one of the calculators I saw said we should have a 6000 CFM fan. But then I heard someone saying that those calculators don't take into account the wasted space from closets, counters, and furniture taking up that space. So we decided to try the 4500CFM figuring we can always add smaller fans later if needed. We won't be adding more though. Even if we open a window in a bedroom with the door closed, the WHF in the upstairs hallway will still pull a strong breeze thru the bedroom window and keep the bedroom cool.
 

Last edited by RPZAG70; 04-08-08 at 07:11 PM.
  #14  
Old 04-09-08, 12:54 PM
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"The vent sits right between the ceiling joists (ours just barely fit) but the fans hang from the rafters in the attic so the fans aren't rattling the joists and the noise isn't right against the vent."

I am not quite clear on your installation- Is your WHF mounted from your roof in your attic or in the floor of the attic? Does that mean you basically have a large attic fan with a large vent to the main house?
 
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Old 04-09-08, 06:57 PM
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The actual fans (there's 2) hang from the roof inside the attic (the rafters) by a couple pieces of bendable metal strappings with screw/nail holes every inch or so - they just kind of hang there in mid-air. Then you cut out a hole in the ceiling (based on a template they give you) and set the grill in it. They said the size of the grill should fit in every ceiling since the space between ceiling joists is usually 14 inches or more (ours was exactly 14 inches). Then you attach the ductwork from the 2 fans to the grill.

Since the fans hang in mid-air and aren't touching anything there's no rattling. And since they're not right next to the grill in the ceiling you don't hear much noise at all when you stand by it. It's quieter than a box fan.
 

Last edited by RPZAG70; 04-09-08 at 07:18 PM.
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Old 04-10-08, 09:03 AM
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I see it now- I read about your fans from your link. Just which rooms did you install the intake grills? On high you have 4500 cfms. I guess that mean 4500 for the 2 intakes(2250/grill). Interesting mounting. We had the 18"Patton installed in the side gable and you could always hear some, but not a problem, noise.
BTW- can someone tell me how to insert a photo. I see they ask for a URL. I have mine on desktop.
 
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Old 04-10-08, 11:27 AM
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Actually, the 4500CFM model only has 1 intake grill. On the back side of the grill (the side in the attic), it has a Y connection, so the ductwork from each of fans connects to the Y. We have a 2 story house with the bedrooms upstairs. The grill is in the middle of the hall upstairs. If you open a window downstairs, you can stand at the top of the stairs and really feel the wind coming up. We'll usually open a window in each of the bedrooms as well.

On low, only 1 fan turns on. On high ,they both turn on. Since each fan just has a regular 3-prong cord to plug into an outlet, you have to wire the 2 outlets (in the attic) to a switch in the hallway. I think they provided the switches as well. So in the end, you flip 1 switch in the hall and the outlet where the 1st fan is plugged into turns on. You flip the 2nd switch and the outlet for the 2nd fan turns on.

Our thought was that since they're right next to the bedrooms we wanted to make sure they were quiet fans. We also chose the bigger model because we didn't want to put a smaller fan in each bedroom.
 
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Old 04-10-08, 11:02 PM
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I see the 2 fans, 1 intake. Don't you think you could have done the same with an 18" Patton suspended from the attic, ducted to your same size intake and on low you would get 4500cfms. That would probably be for around $200 max. rather than your $900-1000. I do like the idea that the fan should be suspended and not mounted on any wood.
 
  #19  
Old 04-11-08, 11:28 AM
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I hadn't really thought of that, but seeing how this is a Doityourself forum... that should work. Course you wouldn't want to climb into the attic to turn it on high/med/low, so not sure how you would wire it... also, you would want to make sure the ductwork fits tight around the fan and the grill - otherwise you're waisting the effectiveness of the CFM.

We certainly like what we have...When I was researching WHF's, I was skeptical about the whole thing. However, after asking friends/family, and Internet research I found that

a) they really do cool your house in the mornings and evenings
b) they really do save you money (compared to running air conditioners)
c) they air out the house really well

But the biggest complaints were

a) they are loud
b) since they suck in air from outside, if you have bad allergy problems this can bring on your allergies.

The posts below are all good ideas to solving the "they are loud" complaint...
 
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Old 04-11-08, 02:17 PM
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Usually the low speed(4500dfms) is good enough, but it is not hard cutting the control switch and splicing in an extension and mounting it from inside the house. I did that with the Patton. Your sounds very efficient.
 
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