Welcome to the world’s largest and most informative whole house fan product overview on the web.
Kurt Shafer here, the publisher of this web site.
I am writing this update on May 29 2016.
Invisco in California has introduced a new energy saving whole house fan that offers you an EC motor powered fan just like the QuietCool’s ES4700. But if you look at the facts, the ES4700 is rated at just over 4400 CFM.
Here is a comparison created by Invisco. NOTE installation included! That IS a first.
The history of whole house fans starts way back in the late 1800s when there was no air conditioning systems. As an example, I was called by a young man in Atlanta GA who said he was renovating a home built in 1902 that had a huge 50 inch diameter fan up over the upstairs landing. In those days big fans were the only way to effectively create a breeze in every home.
It was not until about 1930 that Mr. Carrier invented the first air conditioning system to compress coolant and then expand it to cool air. Carrier Corporation is still one of the leaders in hvac.
Until just about 15 years ago all we had were the big propellers in the ceiling. Then some alternative systems started showing up. Two young electricians in Southern California had been installing the Home Depot systems and they came up with a brilliant idea – instead of having one central machine, make smaller systems that are sized for one bedroom. Thus QuietCool was born and they have dominated the “rafter mounted” market ever since.
At about the same time Airscape and Tamarack Technologies entered the market with unique systems. Tamarack had the first R38 insulated fan with clam shell doors. Airscape offers similar systems with doors right at the ceiling. In 2011 CentricAir in Southern California brought out their German engineered fans. At about the same time Invisco started offering great big rafter mounts.
The most interesting debate is over how many CFM you should buy for YOUR home. I did a study of the different suppliers using my 2800 SF home as an example. Suggestions range from a low of 2700 CFM from CentricAir to a huge 14,421 CFM from Breezepower in Australia. Airscape says 2000 to 3510 if you are in the west or 2800 to 7,020 if you are in the midwest. Tamarack says you need 6 air changes per hour so for 2800 SF they recommend 2200 CFM.
One fact is irrefutable. You cannot have too much air flow within reason.
Here is an interesting factoid – if you open a 2 foot high window 6 inches, the opening is 1 square foot. If you have a 4000 CFM fan with only that window for air, the air coming in is 40 MPH! That’s right – 10,000 CFM will be 100 MPH!