Whole House Fan vs ?

[Malcom "Mal" Reynolds]

I'd love to get a reasonably priced and correctly installed whole house fan, but until then I am using two 18 or 20 inch floor fans rated at 265 watts. I use one from about 8pm until 6am and the second, if necessary, from 1am til 6am.

The problem is that I don't get the airflow I'd like. Fans are in an eastern facing window and western facing door. Open window in western facing bedroom and open door in eastern facing door way.

Temps range from mid 90's to low triple digits. Humidity is often quite low.

The benes from the whole house fan would include evacuating the hot air near the ceiling and not having to move fans around in the morning. Downside would be the cost of fan and installation.

So is it worth going to a whole house fan?

[Ed Pawlowski]

"Malcom "Mal" Reynolds" wrote

Depends on what you think it will accomplish. The fan, installed, will be a few hundred dollars. No matter how well it works, it is still sucking in the hot air from outside. If you don't mind the 100 degree heat, great deal and convenient. Otherwise, buy an air conditioner.

[Jon Danniken]

Get both. Run the AC when it is hot outside, and run the house fan at night to keep the house cool.

Jon

[dadiOH]

Depends. They can suck in nice cool night air but they can also be noisy. Very noisy.

[krw]

They are very noisy but I never found the sound to be objectionable. There was no problem sleeping, well, other than if it was running it was hot.

It really did help keep the house cool, too. I'd run it at night and button up the house during the day. In the hottest days (in lower NY) the house would stay comfortable well into the afternoon.

[Heathcliff]

I have enjoyed having one in the Chicago area. As others have said, it works well when the air cools off at night, and if you run it at night and then close the house in the morning it will stay comfortable until afternoon sometime. Saves on your AC bill. I installed it in the ceiling of the 2nd floor so it sucks air out of the house and blows it into the attic, which is vented, so it is clearing the hot air out of the attic too. To do that, your attic has to have a lot of venting, an area equal to the area of the fan. I had to install a bunch of eave vents to make that work. The louvers in the ceiling get dusty and have to be cleaned periodically. -- H

[Malcom "Mal" Reynolds]

I should have been clearer. I do understand the benes of a whole house fan, what I want to know is there any clear advantage to spending the bucks to install a good one as opposed to using my two fans as I currently use them?

[Ed Pawlowski]

Convenience, more power, better options for window openings, noise is centralized.

[krw]

Certainly. If the attic is ventilated well enough, the whole-house fan will cool the attic in a small number of minutes.

[Malcom "Mal" Reynolds]

but is this bene greater than that which I receive using the existing two floor fans?

[krw]

How are floor fans going to cool the attic? Yes, these fans will put your puny box fans to shame.

[Fatter Than Ever Moe]

I found the whole house fan does a much better job of getting outside air in and the air freshens the house. If you are the kind to worry about heat loss in the winter they can let a lot of warm air into the attic if you don't cover them during the winter season. Moving air around can be noisy or it can be done quietly. Blade size, air speed etc. and they bring in pollen, something to consider if someone has allergies. All in all I like my whole house fan and I use a lot.

[dadiOH]

Do you simply want to evacuate warm air or do you also want to feel air movement? In the former case, just compare the CFM of proposed with the two current to know how much air they move, then figure volume of your house to determine length of time for an air exchange. I imagine the whole house fan will win hands down.

But CFM isn't the only factor for a breeze...much depends on where the air comes from, where it goes and what obstructions there may be. Size of intake opening matters too...the larger the opening the less fan generated breeze through it.

You say you have one fan blowing east, the other blowing west but where are they relative to each other along a N-S line? And where is the bedroom relative to them?

To give you an example, years ago when I was in college I had a long, narrow apartment with a passageway between rooms like this...

_________________________

kitchen _____ _____________

dining bedroom ______ _____________

bath study ______ _____________

living room _________________________ window fan

Windows were on the north in kitchen, east & south in living room and east in others. Closing all windows except one would result in a nice breeze through that window.

[krw]

Wrong. That's one of the primary functions.

[Malcom "Mal" Reynolds]

_____ _____________

window fan

_________________________

I could just open my bedroom window and get great air flow, but if I keep the kitchen door open it cools the thermal mass (concrete floor and ceramic tile) in their which helps moderate the temp during the day and it also helps cool what it can in the living room

[Malcom "Mal" Reynolds]

Currently both fans blow out. I've had the fan that is in the living room moved to the kitchen blowing in. Subjectively that seemed to cool the house better except it didn't facilitate cooling my bedroom and I like to sleep in a cool room. I've tried having the kitchen fan blow out which helps with my bedroom woos but didn't help cool the house too much

[Malcom "Mal" Reynolds]

You can't have more than one primary function. The primary function of the whole house fan is to cool the house, anything else is incidental.

I've seen installations (on-line) where the fan is mounted on roof (no attic)

[krw]

Both the top and the bottom of the insulation are hot, both need to be cooled.

[krw]

What about "that's one of the" didn't you understand?

Then there is no attic to cool, huh?

[Malcom "Mal" Reynolds]

the part where you don't understand that "primary" means singular, not "one of"

so there could be no "one ofs" could there?