How to Install a New Bathroom Exhaust Fan in a Basement

eHow may earn compensation through affiliate links in this story. Learn more about our affiliate and product review process here.

Things You'll Need

  • Screws

  • Cordless screw gun

  • Electrical wire

  • Electrical fittings

  • Wire nuts

  • 4 1/4-inch hole saw

  • Drill

  • 4-inch vent hood

  • Exterior caulk

  • Caulk gun

  • Tape measure

  • 4-inch galvanized metal ducting

  • 4-inch galvanized metal elbows

  • 4-inch metal pipe straps

  • Aviation snips

  • Pipe crimper

  • Sheet metal screws

Image Credit: Comstock/Comstock/Getty Images

Installing a bathroom in a finished basement is becoming more and more popular. Your home will gain selling power when you add a bathroom, and adding one in your basement when you finish it makes perfect sense. A bathroom in the basement will need adequate ventilation, and since basements usually lack a lot of windows, it is logical to install an exhaust fan in a basement bathroom. The exhaust fan will help keep humidity levels down and prevent mold and mildew growth.



Step 1

Select a location for the exhaust fan and mount it in the ceiling joists by screwing it into the joists.

Video of the Day

Step 2

Run electrical wire from the existing light switch to the fan. Wire the exhaust fan into the lighting circuit. Accomplish this by wiring the hot wires (black) through the switch and connecting the neutral (white) wires up outside the switch. The ground wire (green) should be connected to the ground wire feeding the switch. When the switch is turned off, it will break the power connection between the two hot wires and kill the power to the fan.


Step 3

Wire the electrical wire into the fan by connecting the black wires to each other, the white wires to each other, and the ground wires to each other. Use wire nuts for these connections and replace the fan's electrical box cover.

Step 4

Locate where the fan will penetrate the outside of the building and drill a 4 1/4-inch hole with your hole saw. Slide the vent hood pipe stub through the hole and fasten the vent hood to the wall with screws.


Step 5

Caulk the vent hood with a good-quality exterior caulk to prevent water from infiltrating the building.

Step 6

Run 4-inch galvanized sheet metal ducting from the exhaust fan to the vent hood pipe stub. Connect the ducting together by sliding the crimped end into the non-crimped end at least 1 1/2 inches. Screw the joint together with at least four sheet metal screws. Run the ducting up in the ceiling joist space to maintain maximum height for future ceiling installation.


Step 7

Cut the metal ducting if needed with your aviation snips. Crimp one end with your pipe crimper so that it can be installed into the duct system. Continue installing the metal ducting until the fan is connected to the vent hood pipe stub.

Step 8

Secure the galvanized metal ducting with 4-inch metal pipe straps. Provide support every 5 feet to eliminate any sag in the duct system.


Step 9

Install the grille on to the exhaust fan by pushing it into place from below and test the fan out by turning the light switch on. The fan should come on with the light.


Consult local electrical codes when wiring the exhaust fan. Local codes may vary in each municipality on how to wire the fan.

Consult the exhaust fan's installation manual to ensure it is wired per specifications. Each fan can have a slightly different wiring diagram.


Always work on an electrical circuit with the power off. Failure to do so may result in an electrical shock and/or possible death.


Video of the Day


Report an Issue

screenshot of the current page

Screenshot loading...