What is the definition of a whole house fan?
A whole house fan is a ventilation fan installed in the ceiling of your home that pulls cool fresh air from open windows and exhausts the hot air inside the home into the attic and pushes it out the attic vents.
Whole house fans are often confused with an attic fan. Back in the day when whole house fans were invented, they were called attic fans because they were installed in the attic. Even though they are still called attic fans by some people, this is not correct terminology any longer. There are now ventilation products called attic fans that only ventilate the attic, whereas a whole house fan ventilates the entire home.
Whole house fans are also confused with continuous laundry fans. Continuous laundry fans are part of an ASHRAE code called “whole home ventilation.” This is where the confusion stems from.
While a continuous laundry fan is designed to ventilate the home, it does so at a tiny fraction of the airflow of a whole house fan.
A whole house fan can completely change the air volume inside the home with a complete air exchange every 3 to 4 minutes, or 15 to 22 times per hour. At this power level, it would take up to 150 continuous laundry fans to match the airflow of a whole house fan. Whole house fans are the best way to provide whole home ventilation.