With the flip of a switch, a whole-house fan pulls cooler outside air through open windows and sends hot indoor air out through the attic. It can lower the temperature in your home by five degrees in just a few minutes.

Inexpensive energy-saver

One of the biggest advantages of a whole-house fan is the cost - only $150 to $350, compared to thousands of dollars for a central air conditioner. And when used in place of a central air conditioner, it can lower your cooling costs by 30 percent.

Installing a whole-house fan can be a do-it-yourself project if you have some home-improvement experience in wiring, and you have adequate space in your attic. If not, you can hire an electrician or handyman to install it for you.

Use alone or with an air conditioner

You can use a whole-house fan as a cooling system by itself, or you can combine it with your central air conditioner to help cool the house more quickly.

Factors like outside temperatures and humidity levels can affect how well a whole-house fan works. A good rule of thumb is to use the whole house fan when outside temperatures are below 85 degrees.

When the temperature climbs higher than that, or if the humidity level is uncomfortable, it's more effective to use your air conditioner.

Choose the right size

To gauge your cooling needs, multiply your home's square footage by three to calculate the cubic feet of air moved per minute (CFM).

To calculate the required vent space, divide your CFM by 750 - this gives you the number of square feet of attic vent space needed. If your vents are screened or louvered, double that amount.

Allow for good airflow

When you're using a whole-house fan, it's important to allow for good airflow - make sure you leave a window or door open to keep the air moving and avoid damaging your system.

It's also important to insulate the fan opening during the winter - the louvers don't seal tightly, making it a prime place for heat loss.

More from this category

Geothermal

Geothermal wiring system on ground

Capturing the heat from the earth can save you big money on your energy bills.  Learn how geothermal systems work.

learn more

Fix leaky ductwork

Man applying mastic tape to ductwork

Leaks in your ductwork mean the air you've paid to heat or cool is not getting where it needs to go. Find out how to diagnose and fix this common problem.

learn more

Maintaining your fireplace

Inspector looking inside fireplace

Proper maintenance of your fireplace is important to make sure it's working efficiently and safely.

learn more

Radiant floor heating

Kids playing on the living room floor

Heating from the floor is comfortable and very energy efficient.  See how it's installed and how it works.

learn more

Ceiling fans

ceiling fan

A cooling breeze can reduce your need for air conditioning.There are some important things to know about purchasing and installing ceiling fans.

learn more

Installing a heating and cooling system

Two workers installing a new A/C unit outdoors

One of the biggest purchases a homeowner can make is to install a new furnace and air conditioner. Learn what you need to know when faced with this big decision.

learn more

Furnace filters

Man inserting an air filter

Changing or cleaning your furnace filter is one of the easiest things you can do to prolong the life of your heating and air conditioning system.

leARN MORE

Heating and cooling older homes

Radiator in an older home

Don't be scared of an older heating or cooling system. Systems can be inspected or retrofit to maintain the integrity of your older home.

learn more

Space heating and furnace myths

Myth in large lettering

There are lots of "tips" out there that may not be true or safe. Find out how to separate facts from fiction.

learn more