Bigger is definitely better
In general, the larger your home, the larger the fan you should install. And while you can perform complex calculations using climate zone, house construction, etc., in the end, it comes down to this: Undersizing your fan can lead to disappointing performance and results. While, in our experience, no one ever regrets over-sizing their fan.
The ECM power curve
You will need a certain amount of airflow, measured in CFM (cubic feet per minute), to cool your home. Most of the whole house fan operation will be at night, on a low, quiet, maximally efficient setting. Early in the evenings, however, you will want to use a high setting to quickly force the hot air out of your home and return it to a comfortable temperature.
Usually, you can't get one without sacrificing the other, but thanks to the high-tech ECM motors and digital controls we use in our fans, this is a dilemma AirScape owners do not need to be concerned with. All of our fans have been designed to provide maximum airflow at their highest speed. Then, as the speed setting is decreased, airflow is reduced, but energy use is reduced even faster, providing increasing efficiency.
Sizing your AirScape Whole House Fan
The AirScape Sierra and Ventura both come in three different airflow capacities. In general, a bigger house needs a bigger fan.
1500 - 2500 sf
2000 - 3500 CFM
2500 - 3500 sf
3500 - 5000 CFM
3500 - 4500 sf
4500 - 5500 CFM
House under 1500 sq ft? See our compact AirScape 1.7 drop-in unit.