SQLit wrote:
"M&S" wrote in message
nk.net...
Lacustral wrote:

Todd H. ) wrote:

My gut--without researching anything for you--is that a variable speed
whole house fan is probably what you actually want.


I don't need a 1000 CFM whole-house fan - I don't need something to
clear
out the house air in a few minutes. It would require larger ducts and
be
more of a hassle to install.

Laura

Most whole house fans dont use ducts. They simply vent air from the
living space to the attic where it is forced out through gable, ridge,
soffit, roof, vents.

Your question can simply be answered by how quickly you want to change
the air in your home. If you want to cool your home in 1 hour then a fan
that exchanges your homes volume 2-3 times an hour would likely be
adequate. If you are going to leave the fan running longer and cool the
home slower/continuously exchanging the homes volume once every 2-3
hours would be fine.

I have used "attic fans" with limited results for years.

The temp difference, size and materials of the space are what is important.
In my humble attempts if there is less than 10 degrees difference the fan
does squat to very little difference. My home is masonry and has R-40+ in
the attic.

The fan I use is 6000 cfm. Roars like a banshee. I pull the air from one end
of the house to the other. It takes at least 3 hours of 10 degrees
differential to lower my home 1 degree F. Running all night sometimes I can
achieve a 10-15 degree drop. If the differential is greater than 10F then
the results are better. Still takes over night with the banshee running. My
home is ~1100 sqft with 8.5' ceilings.

Sounds pretty much like my experience. I'd been idly wondering if
having the fan mounted in the attic in front of a vent or something
instead of in the ceiling would be quieter, but now I have AC. Oh joy.