Whole House Fan Question - Non-Wakeboarding Discussion

(grant_west) · (grant_west) **Join Date: Jun 2005** 10-21-2013, 10:16 AM

I have a 800 Square foot house and I wanted to install a whole house fan.

The Whole House Fan is a 30 inch belt drive 2 speed with 5700 CFM. on high

I have a few attic vents gable vents and a solar roof vent. My question is how do you know if you have enough roof vents or exhaust for the extra air the newly installed whole house fan is going to be adding to the attic?

(onthecreek) · (onthecreek) **Join Date: Apr 2013** 10-21-2013, 12:51 PM

i bought one years ago. from memory yours sounds way too big on high. recommended CFM was 2 or 3 times the sq footage.

the fan specs should show how much venting it needs in CFM. mine was something like 1 sq ft of vent per 750CFM of fan output.

(grant_west) · (grant_west) **Join Date: Jun 2005** 10-21-2013, 4:52 PM

Its around 2200 CFM on low so that's sized correct for my square footage. But yes on High that's to much cfm

(snork) · (snork) **Join Date: Jun 2007** 10-22-2013, 7:27 AM

for every sqft of house fan you'll need to, at the very lease, match that sqft in external vents