How To Install A Solar Attic Fan? (12 Step Guide)

Do you want to know how to install a solar attic fan?

The great thing about installing solar fans is that there is no wiring like with regular attic fans (here is my review on the best solar attic fans by Natural Light).

In this guide, you will learn…

  • Why using a sawzall (reciprocating saw) is the key to installing a solar attic fan
  • Always use a roof caulk to tightly seal your solar fan
  • How to properly cut out and remove the sheathing hole without damaging your attic
  • The best place to install a solar attic fan
  • How to install your solar fan without smudging the roof sealant

Let’s get started!

solar attic fan install

Why Install A Solar Attic Fan?

According to the Building Envelope Consultants, a poorly ventilated attic can lead to premature roof failure, poor indoor quality, and even damage to rafters and sheathing due to moisture.

A solar attic fan will remove heat during warm weather, and will reduce moisture during cold weather — using free energy from the sun.

And if you have any interest in installing a solar attic fan, now may be the time to do it.

Read Also: What Are The Best Solar Attic Fans By Natural Light?

Step 1: Decide Where To Install The Fan

It is recommended to install solar attic fans 24 inches from the top or ridge of the roof.


This is because the warm air in the attic is already naturally rising towards the ridge.

If you install the solar attic fan lower on the roof, you won’t be catching most of the rising hot air.

The City of Portland recommends that solar attic fans are installed on the southern portion of your roof, and away from any overhanging trees.

Step 2: Locate The Center Between The Rafters

You will want to locate the exact center between the roof rafters or trusses.

You can do this on the roof by using a stud finder.

Alternatively, if your attic isn’t very tall, you can just use a tape measure.

Once you have located the center of the rafters, use a cordless drill and drill a screw through the center (or hammer in a nail).

Read Also: What Are The Pros And Cons of Attic Vent Fans?

This screw/nail will come in handy when you want to pull the sheathing cutout off of the roof, rather than it falling into the attic possibly damaging the ceiling.

Step 3: Pencil a Circular Template Over The Shingles

The solar attic fan should come with a circular cutout template for you to use.

If your attic fan didn’t come with a template, just get a large piece of cardboard, place the solar fan onto the cardboard. Now trace and cutout a circular piece.

Place this circular cardboard onto your roof, with the center over your screw.

Take a pencil, and trace it out over the roof shingles, you can use a marker or construction pencil.

Step 4: Screw A Starter Hole Using the 1/2″ Drill Bit

Now you want to screw a starter hole for the reciprocating saw.

Read Also: What Are The Best Roof Mounted Attic Fans?

Step 5: Cut The Hole Into The Roof Sheathing

Using the sawzall, carefully cut out a hole following your pencil trace.

Before it is completely cut through, grab onto the screw in the center of the cutout.

You don’t want the cut out to fall into the attic and possibly damaging your drywall ceiling.

When you are done, pull out the circular cutout.

Step 6: Lift Up The Shingles To Prepare The Install

Using the flat end of a prybar or other tool, lift up the surrounding shingles about 5 inches so that the flashing of the solar fan will fit under the shingles.

Read Also: How Do Attic Fans Really Work?

Step 7: Cut In Between The Roofing Felt And Sheathing

Now, it is advisable to take your sawzall and cut in between the sheathing and the roofing paper in order to remove any existing nails.

Step 8: Cut a 5″ Notch Into The Roofing Paper

You want to cut in a notch of the roofing paper so that the flashing of the solar fan will fit underneath.

You want to install the flashing in between the roofing paper and the roof sheathing.

Step 9: Do A Dry Fit

Before installing the caulking, do a dry fit of the solar fan.

Install the fan’s flashing under the roofing paper, and see if it properly fits.

How Do You Inspect Attic Fans?

#1. Will It Turn On?

Locate the thermostat (small metal box) usually mounted on a rafter or truss next to the fan in the attic. Turn the temperature knob so it is below the current attic temperature. You can also use a heat gun, hair dryer, or lamp to heat up the thermostat if the attic is cold.

#2. Turn The Blades

If the attic fan doesn't turn on, try turning the fan blades. If the blades won't turn, you may have a seized motor.

#3. Operation Quality

If the the attic fan turns on, are their any weird noises? Does it run smoothly? Can you feel air flow or is it very weak? The fan screen or louvers should not be blocked with debris impeding air flow.

#4. Water Stains

A common problem with attic fans are leaks. Are there any signs of water leaks around the fan on the roof sheathing?

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Step 10: Apply Caulking

Now you want to install two circular beads of roofing sealant to the underside of the solar fan’s flashing.

It is recommended that you install the sealant closer towards the outer edge.

Read Also: What Are The Best Gable Mounted Attic Fans?

This roof caulking is important to keep a tight seal with the roof, and also keep out any water that get’s under the flashing.

Step 11: Install The Solar Fan

Now it is time to install the solar attic fan under the shingles, and in between the roofing felt and the sheathing.

You want to lift up on the attic fan as much as possible so that you avoid smudging the roof sealant as you slide it in.

Before installing any screws, you want to make sure the fan is properly sitting in the roof and is level.

Now it is time to install two screws into the bottom flashing, two on each side, and two screws at the top.

Read Also: How To Install Roof Mounted Attic Fans?

Step 12: Install Caulking On Top

Now, you want to install the roof caulking on top of the unit at the sides, in between the fan and the shingles.

It is also a good idea to put some caulking over the screw heads.

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