Whole house fan anyone?

[Dan Karachio]

Somehow my wife has convinced me to avoid bringing up the AC units all summer and I think we just might make it. We have insulated the attic with blow in cellulose, added some roof vents and a ceiling fan and along with some window fans it is staying cool up here. However, plenty of times in the evening it is much cooler outside and I just can't seem to get the air flow working. When we were kids we had an attic fan that sounded like a small Cesna airplane taking off, but boy did it keep the house cool.

Does anyone have experience with newer attic or whole house fans? Can you recommend models or other tips? Thanks in advance.

[Mitchell Andrus]

My house was built in '27 and the whole house fan that I installed when we moved in works great. If you don't mind the breeze, leave it on low all night. I prefer to run it in the pm when it's cool, off at 11:00. It's enough to cool the house for sleeping.

When it's warmer outside than inside, close the windows. When it's cooler outside than inside, open a window in each room and run the fan. Makes sense. Duh.

We've got window A/C units but run them maybe 15 or 20 times a year, otherwise fresh air rules.
.

[Richard M. Wolfe]

When I remodeled the house I only had room for the smallest fan, which is direct drive and very noisy. But I'm still glad I put it in for the air I can move through the house. One of the best ones I've seen was a squirrel cage belt driven unit. It was much larger than mine but moved a lot more air with a lot less noise.

[Dave Johnson29]

Does anyone have experience with newer attic or whole house fans? Can you recommend models or other tips? Thanks in advance.

Dan,

I am assuming a whole house fan is just a swamp cooler without the swamp and pump? I have been pondering this issue for some time. Currently of an evening when it is cooler outside than in, I use a square industrial fan at one the doors. It works, just not very efficiently as there is some closed loop recirculation around the parts of the screen door above and below the fan. It is pretty noisy too.

I did not want to pay 600-bucks for a 4,000-cfm swamp then toss half of it away as all I need is the fan. I too would be interested in brands, costs and where to buy.

[Pat Germain]

Whole house fans are popular in Colorado. The temperature plummets as soon as the sun goes down. It works very well to suck in the cool air after dark and push out the hot air. But if it's hot outside, a whole house fan is useless.

One note of caution. A friend of mine had a new house built just a few years ago. It included a whole house fan. But every time he turned it on, it would blow out the water heater pilot light. He would wake up in the morning with no hot water. I don't know if he ever did get that poblem worked out.

A whole house fan may not be available at the local home center. But they are still pretty common. I'm sure you could find one online or at an HVAC supply.

Another fan I saw a lot in Virginia was an attic fan. It just sucked hot air out one end of the attic. Most are controlled by a thermostat which prevented them from running when it's cold. These fans significantly reduce the attic temperature. People who installed these fans told me it made their homes much more comfortable in Summer and their A/C didn't have to work nearly as hard.

[Scott T Smith]

[QUOTE=Dave Johnson29;1186750]Dan,

I am assuming a whole house fan is just a swamp cooler without the swamp and pump? QUOTE]

Not quite. The whole house fans that I'm familiar with in Texas were louvered units that installed in-between the ceiling and the attic, in a common area such as a hallway.

They work by sucking the hot air out of the house and pressurizing the attic, which in turn forces the hot air out of the attic through the vents. You get the added benefit of cooling down the attic, which also cools down the living spaces.

You need to open several windows throughout the house in order to provide adequate air to them.

A friend of mine in Austin has one in his house, and one fall day he started a fire in his fireplace, which smoked up the house (not quite cool enough to draw properly). He thought that he'd use his whole house fan to suck out the smoke. Bad idea - it sucked flames three feet out of the fireplace into the room (I was standing near the fireplace and it scared the hell out of me!).

Lots of older homes (that were poorly insulated) had them in Texas, and they worked well.

Graingers sells a very high quality unit (Dayton brand).

[Ben Franz]

Attic/whole house fans are common where I grew up in the midwest. I had one in my last house in CA and installed a few for clients over the years.

A key issue is adequate attic ventilation - the fans draw a lot of air through the house and it has to get out of the attic through ridge, roof mount or gable vents.

I've seen ads in Fine Homebuilding and Journal of Light Construction for newer units that have better shutter systems that are insulated to minimize heat loss in the winter. You might look through these mags for info.

[Dan Karachio]

Thanks everyone. Point taken, I will not install one near the fireplace!

We probably have enough ventilation in our attic, but some of the roof mounted units look interesting. The fan is in the roof and a large hose runs down to the ceiling. Seems to take care of ventilation and noise. Right?

http://www.suburbanfan.com/roof-mount-direct-exhaust-whole-house-fan

$650 plus half that much at least for an electrician and install...

[Bonnie Campbell]

I have an whole house attic fan. The one I have IS noisy. Can't hear it outside running, but sounds like an airplane inside! I've probably used it more this summer than the AC. I'll turn it on in the evening once it starts cooling outside, then on for about an hour in the morning. One word of warning, if it's high humidity outside, remember you're sucking that humidity inside. I've had blinds dripping from the humid air being drawn in. The fan has more than enough draw to air out a 3500 ft house. No idea what kind of fan it is, but this one is just mounted facing up into the attic on the attic floor. There is a small fan above there, but we've plenty of other venting area out of the attic to handle it. Only thing I wish is that it ran quieter. My one little dog is terrified of the noise whenever I run it.

[Dave Johnson29]

$650 plus half that much at least for an electrician and install...

Dan, I did some searching and that is a ridiculous price for what you are getting. Some sites I found were even worse at $800 for a 1500 cfm unit.

Here's one that includes the doors for a better price...
http://www.airscapefans.com/whole-house-fans/airscape10.php

Even better here...
http://www.quiet-cool-whole-house-fans.com/Products

Looking at the fans they probably run from 110v so you could just run an extension from an inside outlet. Use a cheap timer on it that turns on at say 6:00pm and off whenever.

I have found enough information to understand the systems and will look into making my own. If I can't do it for under a 100-bucks or close thereto, I will eat the damn thing.

[Eric Larsen]

As long as you want what's outside, inside, they're great. (Any allergy sufferers in your house?)


Spend the extra for a quiet one, you'll be glad you did. I'm certain my dad went deaf turning up the TV to compete with the attic fan.

As for installation, I'd consider this a DIY project and wire it with either a thermostat switch or a timer switch, depending on what's best for your climate. I'd budget four strong arms and five hours for this project. (Less hours if your current attic opening will accommodate the fan.)

EDIT -- I'm doing an attic ventilation job as well, but I definitely DON'T want what's outside, inside. So I'm adding a 1500 cfm fan and gable vent. I'm also paying for the install, because I don't do 30-foot ladders. If anyone knows about a 20"x20" gable vent I could install from inside the attic, I'd REALLY like to hear about it. I simply know too many gimp roofers, and I'm accident prone. No roof work for me, ever.

[David G Baker]

When I lived in California Home Depot carried the hall way between the joists type whole house fan for around $135 for a 36 inch blade belt driven fan. My stepdaughter had one in her house that was similar. It kept the house very cool but the fan was quite noisy. You will have to make sure that your attic space has ventilation large enough to handle the volume of air that the fan puts out.

[Dave Johnson29]

Home Depot carried the hall way between the joists type whole house fan for around $135 for a 36 inch blade belt driven fan.

Yesterday I checked with HD and Lowes. Both carry the ceiling versions for around $250. They use a 1/2 hp motor so no big electrical or weight loads involved.

Good point about the attic vent sizes to handle the air flow.

I saw one interesting type online that was suspended on straps to isolate it from the woodwork. it then had a duct to the grill in the ceiling and they claimed 52db for noise. Given that 30db is normal household "quiet," that sounds pretty good to me.

[David G Baker]

Dave J,
Guess that fans are like almost everything else, doubling in price or more in 10 years.
The isolated fan sounds like a great idea but the movement of the large volume of air will make its own sound but the sound is much more tolerable to me than too much heat inside of my home. 52db is good if it is true.

[William Payer]

I have had a whole house fan in my house for 29 years now. I think its great, allowing us to use the AC only when necessary (wife dislikes AC). Many previous posters have covered important points such as:

1) Adequate attic ventilation needed for fan to work well. (We have 10 "can" type vents as well as 2 side gable vents and a ridge vent)

2) Do not start fan until at least two decent sized windows are open. THe draw of a large fan can (and will) blow cause downdrafts in chimneys, often blowing out pilot lights and resulting in raw gas in the house(or as one person stated the fireplace worked in reverse and was a fire hazard)

3) A winter cover can be made by any woodworker to minimize heat loss through the louvers. (I have a wooden frame on the ceiling that the louver attaches to, and the cover attaches to this frame via t-nuts embedded in the frame. I have a 1.25" wooden frame with quarter inch ply rabbeted within, and 1 inch stryofoam on its underside against the louvers. The entire perimeter has foam weatherstripping to seal out drafts)

One point no one has touched on is SAFE USE with a fan of this type.

When running , this type of fan creates a lot of air movement throughout the house. In case of a fire, this air movement will accelerate the spread and growth of a residential fire. Some time ago I saw a video test of a sample house with and without a whole house fan. Fires were started in the same place and manner and the time noted before the fire officials deemed it would be too difficult for occupants to get out safely. Without a fan, the family had about 3-4 minutes before it became disasterous, with a fan running the time was cut to under one minute!

Moral? Do not run the fan when everyone is asleep. You need someone in a waking state just for safety purposes.

PS. Some fans came with a thermal limiter device. It is mounted in the attic directly above the fan (within 1-3 feet of the blades) If a fire were to break out, the temp of the air being drawn through the blades rises, breaking the electrical circuit to the fan.