Whole House Fans Sizing Considerations

Choosing the right size whole house fan for your home is about more than simply figuring out square footage inside your home and going with it. There are other considerations to take into account in order to maximize the effectiveness of your whole house fan.

How High are Your Ceilings?

People who have higher than average or cathedral ceilings have a great total number of cubic feet of air space in their homes. If your home has high ceilings, it’s a good idea to consider a whole house fan that’s larger than the actual square footage of floor space in your home calls for.

How is Your Home Configured?

Homes that have odd configurations or shapes, such as ranch style homes, will need whole house fans that are a bit larger in order to accommodate the additional degree of difficulty corners and other shaping issues cause when it comes to moving air.

Since whole house fans work by pulling air from the outside into your home, fans that must work around unusual corners and such must work harder to draw in air. One alternative would be to use the existing ductwork in your home for moving the air. Consult with a local heating and cooling professional for advice on how to make that work in your home.

Is Your Roof Ventilation Up to the Task?

One more question you should ask and answer before installing your whole house fan is whether or not your existing roof venting is adequate for the task of venting the air your whole house fan will pull in. In order to bring more air into your home, you’re going to have to vent an adequate amount of air out of your home to compensate. This means you need to have enough rooftop ventilation to handle the task.

How Breezy Do You Want Things to Get?

Some people have a preference for no breezes inside the home. While it takes longer to cool your home with a whole house fan that doesn’t produce breezes, it is still possible to enjoy some cooling effect.

People who don’t mind gentle breezes, though, in exchange for faster cooling, will find that they need fans capable of moving more cubic feet per minute than those who prefer no breeze at all.

Getting the Sizing Right

It’s important to get the right size fan for your home. Fans should be sized by the cubic feet per minute (cfm) of cooling power they provide. The Department of Energy provides a handy formula for helping you determine the size of whole house fan you need in your home.

You’ll need to calculate the amount of air in your home in cubic feet by multiplying the square footage of floor space with the height of your rooms (floor to ceiling) Then multiply by 30 or 60 (this refers to air changes per hour and varies according to the power you’ll need). Finally, divide by 60. The answer is the cubic feet per minute of air your house requires a whole house fan to move.

There’s no denying the benefit of using whole house fans to cool your home in a cost effective manner. However, getting the size right is critical. These considerations will help ensure you do.

Have questions about whole house fan sizing? Give us a call at 1-888-229-5757.