Picture of confused guy


There’s a lot of confusion associated with attic fans and whole house fans. Many think they are one in the same, but they are not. These two fan types work very differently and offer different benefits to homeowners.

Attic Ventilation

To understand the function of an attic fan, you first need a basic understanding of attic ventilation. Attic ventilation is the combination of intake and exhaust vents that circulate air in your attic, allowing fresh air to flow in while expelling stagnant, hot, or moist air to the outside. Proper attic ventilation helps prevent heat and moisture from building up in your attic during winter and prevents hot attic conditions during summer months.

Attic Fans

The primary function of an attic fan is to improve attic ventilation (air circulation in the attic). An attic fan is installed on the roof or gable of the attic. It regulates the heat level of an attic and accelerates air circulation by rapidly expelling air out of the attic while drawing fresh air in through intake vents, typically installed at the eave of the roof.

An attic fan is equipped with a thermostat that senses the temperature of the attic and activates the motorized fan when the attic reaches a preset, specified temperature. Attic fans can also be equipped with a humidistat which measures the relative humidity in the attic, rather than temperature. The humidistat is programmed to activate the attic fan when preset humidity levels are detected.

Poor attic ventilation can lead to a whole host of problems.  Click here to read more about attic ventilation>

Whole house Fans

The primary function of a whole house fan is to accelerate air circulation for the “whole house”.  A whole house fan is often used as a natural air conditioner, rapidly cooling living spaces. Whole house fans are installed in the ceiling, in a centrally located area, ideally on the highest floor of the home.

While whole house fans can include a thermostat, more often these fans are manually activated. For the whole house fan to work effectively, windows on the lowest level must be opened to allow fresh outside air to be drawn into living spaces, displacing warm air that is drawn up through the whole house fan and exhausted through the roof.

For homeowners that are away during the day, running an air conditioner for 8 hours or more during hot summer months can get very expensive. On the other hand, with no air conditioning, living spaces can become intolerably hot when a home is closed up all day. A whole house fan can eliminate this problem. When the homeowners arrives home, all they have to do is open up a few windows and activate the whole house fan. Stagnant, hot air is removed from all living spaces and replaced with fresh cool air from outside in a matter of minutes.

While whole house fans will often cost two to three times that of an attic fan, the cost savings and increased comfort are often easy to justify.

Attic Air Services

We provide attic insulation and attic ventilation including attic fans and whole house fans to homeowners in Chicago and all Suburbs. Call us for a free attic assessment today at 630.830.3870.