Is it OK to install 2 whole house fans in one house?

Here is some information about installing two whole house fans in one house.

As long as the house square footage merits the need for 2 Whole House Fans (see the sizing formula on Air Vent's website) and the attic vents (that is, the combination of intake vents and exhaust vents) are enough to provide enough airflow outlets for the running whole house fan, it should be OK.