What is a Whole House Fan? How does it work?….. Better yet, How does it compare?

What are Whole House Fans?

A whole house fan is a ventilation cooling system that uses less energy than a traditional air conditioner. This energy-efficient system works by pulling cool, outdoor air into your home and out your attic vents. This helps keep the mass in your home cooler than an air conditioner can. These whisper-quiet and energy-efficient wonders are the #1 residential cooling & ventilation appliance on the market. With a whole house fan, you’re able to turn off your most expensive appliance, air conditioning, while improving the air quality and comfort of your home for just pennies per hour. A whole house fan system is installed in the ceiling between the attic and living space.

Whole House Fan vs Attic Fan

Whole house fans and attic fans are often confused. However, they are not the same thing.

A whole house fan is used for cooling both the home and attic. You typically run a whole house fan during the evening through into the early morning – basically any time it is cooler outside. This cools, ventilates, and exhausts all the hot, stale air in your home and attic. You would never run your whole house fan during the middle of the day when it is the warmest. This is where an attic fan comes in.


Attic fans ventilate and exhaust your attic only. You use them primarily during the day but they work well in the evening and night as well. They pull air from the outside through existing vents in your attic. This allows your attic to stay within 10ºF of the outside temperature at all times when the fan is running. Without an attic fan, your attic can get up to 150ºF during the summer, which can ruin the integrity of your home and cause high electric bills.

The best system combines an attic fan and a whole house fan to cool, ventilate, and exhaust the entire home, day and night, and year-round.

Attic Fans – Attic fans ventilate only the attic to reduce heat buildup and humidity, they operate year-round. Even during the winter months, homeowners can use an attic fan. In the winter, moisture and mold can build up due to the air in the home being very warm versus the air in the attic being very cold. The snow on the roof then becomes ice and holds the excess water. This is called ice damming and it is what creates mold, mildew, and premature roof rotting. With an attic fan, the constant flow of air in the attic lowers the overall humidity level and helps keep the attic healthy.

The best system combines an attic fan and a whole house fan to cool, ventilate, and exhaust the entire home, day and night, and year-round.

Whole House Fans – ventilate the whole house, including the attic and living space by bringing cool air from outside into the house to cool it and force the hot air out through the attic vents.

The whole house fan pulls air in from open windows and exhausts it through the attic and roof. It provides good attic ventilation in addition to whole house cooling. Whole house fans should provide houses with 3 to 6 air changes per hour (varies with climate, floor plan, etc.—check with our experts to determine what is appropriate for your home).

Whole House Fan vs Central Air and Window Units

Whole House Fans should never be used simultaneously with air conditioning of any kind – central air or window units. These systems can both reside in the same home and be used to complement one another.

Central Air Conditioning – cools the air with a chemical (like Freon) and circulates it within the house but does not pull in fresh air from the outside

Window AC Units – pull outside air and cools it with a chemical (like Freon)

Whole House Fans – Pull cool outside air into the house to cool it, then push the hot air in the house out through the attic


When to run your whole house fan:

When to use a Whole House Fan and how is a crucial aspect of receiving as many benefits as possible from these fans. The first important step is to ensure that the outdoor air is a temperature you would like in your own home. If it is, simply open 3-4 windows 2-3 inches wide and turn on your whole house fan. This process will flush in the outdoor air and flush out your stale, indoor air. You will have complete air exchange within 3-4 minutes!


Whole House Fan vs Ceiling Fans

Ceiling Fans – just move air around; they don’t pull in fresh or cooler air

Whole House Fans – Can improve the indoor air quality by filtering in fresh air and filtering out polluted air

Whole house fans combined with ceiling fans and other circulating fans provide acceptable summer comfort for many families, even in hot weather.


Call us today to schedule an appointment for a Quiet Cool Whole House Fan. We serve Fort Collins, Loveland, Greeley, Longmont, Boulder, Windsor, Wellington, and the surrounding areas. Schedule an appointment with an expert you can trust. 970-399-9940