Some whole house fan manufactures are overstating the “real” cfm rating of their fans by quoting the cfm rating of the fan “free standing” before it’s connected to the rest of the system. The actual CFM rating can be as much as 30% to 40% less than what is stated. For this reason, it’s important to pay attention to the square footage that the whole house fan is recommended to cool.
Attic Ventilation (Beware of “one size fits all” whole house fans)
Whole house fans pull air into the house through open windows or doors and ultimately all that air is blown into the attic. For this reason, it’s important that there is sufficient attic ventilation to properly exhaust the amount of air that is blown into the attic. If there is not enough venting, you can over pressurize your attic causing hot dirty attic air to be blown back into the home and the fan to prematurely fail. All our CentricAir systems specify the required amount of attic ventilation under the Specifications tab on each individual product page and we always verify proper attic ventilation before installing your whole house fan system.