Attic Fan or Whole House Fans

[Matt]

Yes, by all means, get one.

[Bgreer5050]

Any thoughts and/or recommendations appreciated.

Thanks

[Edwin Pawlowski]

Attic fan cools the attic. Nice if you are running air conditioning as it will get rid of heat that can radiate down into the rooms below.

Whole house fan pulls the outside air through the house so you do not have to run air conditioners on a cool evening. Right now, I'm sitting near a window and had to close it down some as it is pulling so much cool air right across me.

Attic fan is god in very hot climates where you will be running AC all summer. Whole house is better in moderate climates with cooler evening where the AC would not be needed if you can bring in the cool outside air. By opening and closing windows you can control the flow of air through the house. If you run it a night and close the bedroom doors, it is of no value.

[Frank Boettcher]

Ditto to the above. I have both and live in a brutally hot and humid climate. Use the whole house fan in the spring and fall and the attic fans are set on thermostats to provide additional venting to the attic when the temperature goes up

Pros:

Whole house fan brings in lots of cool air during the spring and fall, good for sleeping at night.

Attic vent fans keep the temperature down in the attic, reducing the AC load and extending roof shingle life.

Cons:

Whole house fan seems to bring in a lot of dust with it and if you have allergies you can forget it.

Attic vent fans don't seem to last. the little motors seem to burn up about every two seasons. $50 bucks a pop to replace and I have two of them.

[trader4]

"Cons: Whole house fan seems to bring in a lot of dust with it and if you have allergies you can forget it. "

Also, they don't help with humidity. And they don;t seal perfectly either, so in the winter, you'll have some energy waste.

A lot depends on the climate and how much you can really use it.

[barry]

Actually, you may be able to have both, in one.

I recently installed fan rated @ 1540 cfm in S attic gable. About 15" diam. If I leave door (which is sealed) to attic closed, fan does decent job drawing from N gable end. Fan has make-on-rise adjustable temp-switch. Temp rise on floor below is greatly reduced; ditto thermal stress on lumber & roofing above.

If I leave door to attic open, and open distant windows below, fan ventilates whole house very nicely. For fall, and beyond, I'll have to wire in some sort of timer-switch in parallel w/t-stat. Or, a second temp switch with a lower set-point, switched in parallel with first. (Or even a timer in series w/ second temp-switch for whole-house, in parallel with attic-only temp-switch.)

Some folks I've seen in the past use 3' or larger diameter fans sucking from house up through attic. And may even need them. In my case, such a fan would suck in the screens or lift the roof-deck, or both.

[John Hines]

I installed one of these spring:

It is much smaller and quieter than the old 30" fan with aluminum louvers (heat loss), which would pull papers off of tables, and blow out the pilot light in the water heater if it ran w/o opening windows.

Expensive, but very nice fan.