Installing an Attic Fan

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Attic fans provide much-need ventilation to an attic, but they can be challenging to install if you've never done it before. This guide will show you exactly how to do it, from the first step to the last.

Locate the Area Where You Wish to Install the Attic Fan

The southern side of your roof is the best place, since an attic fan works best in full sunlight. Using a reciprocating saw or jig saw, cut a 13-inch diameter hole through the roof material and sheathing, then remove the circular plug. Try to center the hole between the roof rafters to ensure clearance on the underside.

Slide the Unit Into Position from the Lower Side of the Roof

Make sure that the lower portion of the flashing is underneath both the existing roofing material and the underlayment (felt). The higher portion of the flashing should be on top of the existing roof material.

Fasten the fan according to normal flashing requirements for the appropriate roof type. Reinstall any pieces of roofing material necessary to cover the sides of the flashing.

Installation Tips

Your attic fan will work best in full sunlight. Southern exposure on the roof is ideal. Avoid installing your fan under overhanging trees or other structures creating shade.

Your attic fan will also be most effective if installed as close as possible to the top ridge, as natural convection causes hot attic air to rise upwards.

The attic fan should be used in conjunction with existing soffit or gable vents to create a complete attic ventilation system. Your existing home should already have some form of soffit or gable ventilation.

If your attic presently has no ventilation and the attic fan will be its only form of ventilation, it's possible that negative pressure could be created by removing the existing air while no outside air is coming in to replace it. It's unusual for a home to be this airtight, but if so, this problem can and should be overcome by the addition of soffit vents.


To ensure optimum performance, clean the top of the solar panel with warm soapy water from time to time. The fan motor is a brush-type motor. Brushes may need replacement after several years of operation. This can be done from the underside with a screwdriver in about five minutes.