Does My Whole-House Fan Save Energy?

Do you enjoy running your whole-house fan?  Aren’t they great?   Ordinarily installed in the ceiling, these fans pull air out of the house and push it into the attic.  A question many people ask is, do they really save energy?

Of course each home is different and an energy audit is the best way to know for sure whether your whole-house fan is saving energy.  That said, for most homes in the St. Louis area these fans waste more energy than they save.

Positives of a House Fan

On the plus side, we have a small number of beautiful, cool days each spring and a few more in the fall when we can turn on our whole-house fans, open our windows, and pull outside air through the house.  This can be very enjoyable if you like to fill your house with fresh, cool, outside air.  On those days, doing this can save energy if it allows you to be comfortable without having to run your air conditioner. 

Negatives to Having a House Fan

On the minus side, the number of such days each year is small in the St. Louis area.  For the number of days when you can run your fan instead of your air conditioner, there are many more days when the fan is just a hole in your ceiling.

Most whole-house fans have louvers that allow air to flow freely between the house and the attic.  Air also leaks around the framing.  All these leaks waste energy and money.  In the winter, warm heated air from the house is lost into the attic.  In the summer, the stack effect forces cool air from the house into the attic.  Your furnace and air conditioner both have to work harder, most of the year.

The Home Energy Solution!

The best fix is to remove the fan and cover the hole with drywall or some other material.  Alternately, an air sealed and insulated box can be built over the fan in the attic.  The box can be opened if you want to use the fan and then closed when the fan is not in use.

It’s your house.  If you keep your whole-house fan because you enjoy it, then that is great.  Just don’t keep it to save energy.  In our climate, most whole-house fans waste far more energy than they save. Contact us today to schedule your home energy audit! We can help you understand where your home is using and losing energy, seal air leaks, and identify the affect your house fan is having on the rest of your home.