Update 8-17-18 QuietCool is now 4th in the order of highest performance because the company has just complied with the state of California by displaying the true HVI-916 air flow like the other companies do now. But QC still insists on showing a misleading higher CFM value – here is an example from their web site:

Name STL PRO-7.0X Airflow* Hi:6996 CFM HVI-916 Airflow (CA Title 24)** 5200 CFM
The star is “*Listed airflow specs are tested via a device that is calibrated to NIST standards.” which is meaningless because NIST does not have a standard for testing like the HVI-916 has.
So the list below had QC in 2nd place but now shows them 4th.

List shows highest air flow offered per HVI-916 testing.

Thorwaldson    6320 CFM (Testing done to HVI-916 and submission in process to CA CEC )
VentCool          6123 CFM
Airscape           5350 CFM
QuietCool        5170 CFM
CentricAir        3860 CFM
QA-Deluxe       3396 CFM (this is a new supplier created by the owners of CentricAir)
Tamarack         3400 CFM (this is neither a rafter mount like those above nor is it the traditional ceiling mount.)

For more about CentricAir and QA-Deluxe go here – https://www.centricair.com/new-product-line/

Here are all the other suppliers.

Air Vent
Dayton/Grainger
GAF/MasterFlow
Marley
Triangle Engineering
TPI

And in Australia

https://AussieWholeHouseFans.com.au/
http://www.WholeHouseFans.com.au/
http://www.Invisco.com.au
http://www.Cardiffair.com.au/

Get YOUR home evaluated – email kurt@wholehousefanguy.com
Kurt Shafer YOUR Whole House Fan Guy 800 579 5018