How to Vent a Bathroom Exhaust Fan

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Things You'll Need

  • Aluminum coil dryer hose

  • 2 Large c-clamps (circle clamp)

  • Drill

  • Outdoor exhaust vent

  • Flathead screwdriver

  • Vertical electric saw

  • Exterior silicon caulk

  • Tape measure

  • Eyewear

  • Gloves

  • Pencil

Vent a Bathroom Exhaust Fan

Besides the kitchen, another critical place to have an exhaust fan is the bathroom. Fans are easily inserted and attached to the ceiling and connected to an electrical source. Exhaust fans draw air and moisture from a room with a reverse fan. If you don't connect a vent to the exhaust fan, however, you are just pulling this moist air into the rafters of your house. Venting the moist air from the bathroom exhaust fan to outside can easily be done with the proper tools and techniques.


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Step 1

Get into the roof crawl space above your bathroom. If this is not possible, unscrew the exhaust fan from the ceiling and allow it to hang freely by its wire connections. Measure the circular vent connection hole size on the exhaust fan. Buy an aluminum coil dryer hose, along with two c-clamps just a bit bigger than that diameter.

Step 2

Place a c-clamp on the hose. Connect the hose to the exhaust fan vent hole. Tighten the hose to the exhaust fan vent hole by tightening the c-clamp screw.


Step 3

Look into the exhaust fan hole in the ceiling and identify the closest outside wall. Measure your wall height.

Step 4

Re-screw in the exhaust fan to the ceiling with the newly installed vent hose connected.

Step 5

Go outside to the wall closest to the exhaust fan vent hose. Measure the same height up from where the floor would be in the bathroom to where the ceiling was. Add 6 inches to your measurement to clear possible 2-by-4s in the ceiling rafters. Mark that measurement with a pencil.


Step 6

Drill a hole in your siding 3 inches above where you mark your bathroom wall height, plus 6 inches. The 3 inches extra is because the standard diameter of vent hoses is 6 inches, so the drill hole will be the center of the vent.

Step 7

Pencil in the size of the vent hose, with the drill hole being the prefect center. You can use actual piece of dryer hose for an outline.

Step 8

Insert the electric vertical saw into the drilled hole and cut out the circle pattern.


Step 9

Reach into the hole and grab the vent hose. Pull several inches of the hose through the hole (it should be pretty snug.)

Step 10

Place a c-clamp on the hose. Connect the hose to the outdoor exhaust vent hole. Tighten the hose to the outdoor exhaust vent hole by tightening the c-clamp screw.

Step 11

Apply exterior silicon caulk around the hole in the siding and on the back of the outdoor exhaust vent.


Step 12

Push the outdoor exhaust vent in until it is flush with your house. Screw in the four screws that hold the outdoor exhaust vent to your home.


Wear protective eyewear and gloves.