Attic Exhaust Fans

Attic Exhaust Fans are usually attached to a thermostat located in the attic. The thermostat can be set so that the fan starts when the temperature reaches a certain temperature between 60 and 120 F.

Solar powered attic exhaust fans  run whenever the sun is shining. Unless they have a battery backup they do not run at night so you do not have ventilation when it is the coolest outside.

Attic exhaust fans need intake ventilation. If there is not cool air entering the attic, the hot air cannot get out.  

Before installing an attic exhaust fan -
  • Do not install an attic exhaust fan if you already have rooftop or gable vents. The fan will pull air in from the rooftop or gable vents, “short circuiting” the attic ventilation system. Attic ventilation systems are either powered or unpowered. If you install an attic exhaust fan you should plug any existing rooftop or gable vents and install more soffit vents.

  • Rooftop fans are more powerful and are easier to install than gable fans.

  • Solar powered fans do not require electricity but are not as powerful as electrical fans.

Mushroom shaped attic exhaust fan colored a weathered gray.

Rooftop Exhaust Fans, also called powered roof ventilators or attic fans, are generally available in 3 sizes. Depending on the size of the fan, they may be available in gray, mill, or weathered wood.

Powered Gable Ventilators are also generally available in 3 sizes. They are installed with automatic shutters that open when the fan comes on.

Solar Roof Fans are cute. They are more expensive than regular electrical attic fans and they do not move as much air. They run whenever the sun is shining so no controls or wiring is needed. However, most models also shut off as soon as the sun goes down or it gets cloudy. That means you have very little ventilation going on late at night when it is cool and you want to cool off your home.