A Diy Guide to Installing a Bathroom Exhaust Fan

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The three main type of exhaust fan vent caps


Installing a bathroom exhaust fan is a relatively easy project for any moderately skilled do-it-yourselfer. In the first part of this article I will cover the installation of the fan unit itself and in the second part I will cover running the electrical. There are many different types of vent fan units-exhaust fan units, exhaust fan units with light, exhaust fan with light and night light, etc but they all install alike. The difference lies in the electrical wiring. The other differences in installation lie with the way they are vented using a roof cap vent, a soffit vent or a through the wall vent. This project will require working on ladders and the roof of your home so if you aren't comfortable working at heights this project isn't for you. Before undertaking this project I recommend that you read my article on ladder safety.

Time required: 6 to 10 hours depending on skill level and structure.

Tools that you will need to complete this project

· 6 foot step ladder

· Extension ladder

· 3/8" drill/driver

· Zircon Stud sensor Pro LCD Electronic stud finder

· Large layout square/speed square

· Jig saw

· 4" Hole saw

· 1/4" X 18" Irwin's installer bit

· 3/8" Spade bit

· Tape measure

· Lineman Pliers

· Diagonal Pliers/wire cutter

· Wire strippers

· Long nose pliers

· Flat blade screwdriver

· Phillips Head screwdriver

· Wire fishing tape

· Digital Multimeter

· Caulking gun

· Tarps/drop cloths

· safety goggles

· Dust mask

Materials and supplies that you will need for this project

· Vent fan/light unit90° sheet metal elbow

· 12' connector duct

· Roof vent cap or through the wall vent or soffitt vent

· Aluminum foil duct tape

· 12/3 w/gr romex cable

· toggle switches

· Old work box

· Assorted wire nuts/wire connector

· Silicon caulking

Installation procedure

1. Begin by making a mark on the bathroom ceiling where you want to install the vent fan/light unit. The best place to locate these units is halfway between the toilet and the shower/tub unit. Using the stud finder make sure your mark isn't right over one of the rafters, then drill a reference hole using the Irwin 1/4" X 18" installer's drill bit. Drill completely through the bathroom ceiling and into the attic space.

2. Using that hole as a reference point remove the attic floor boards as needed and remove any insulation present. If your home has blown in insulation you may want to use A shop vacuum to remove it before proceeding further

3. Back in the bathroom, layout the opening using the layout square and then cutout the opening using the jig saw. A reciprocating saw or a hand drywall saw will also work. Before completing the cut support the waste piece with one hand so it doesn't fall and take some of the good plaster or plaster board with it

4. Attach the 90º elbow to the vent fan housing with the elbow pointing straight up. Remove one of the 1/2 K.O.s (knockouts) from the fan units electrical splice box and install a 1/2" Romex Cable connector. Then slide the four metal support brackets into the tabs protruding from the vent fan housing

5. Back in the attic center the vent fan on the ceiling opening and attach the fan support brackets to the joists. Secure the supports to the joists using 1 1/2" drywall screws.

6. Attach one end of the vent duct to the elbow and tape securely using the Aluminum Foil Duct tape

7. Now locate a spot between to studs within 6 feet of the vent fan to install the through the wall vent cap. A through the wall vent cap or a soffit vent is preferred over a roof vent cap because there is less chance of a water leak. Take several measurements from nearby references like a window or some other easily identified references so you can use the to locate the spot on exterior wall of your home

8. Step up your extension ladder and drill a 4" hole at this location. The hole doesn't have to be centered exactly between the studs so long as it is between the studs

9. Install the wall vent assembly using the foam gasket and a bead of silicon caulking to seal it

10.Connect the vent duct to the wall vent tube and tape with the Aluminum Foil Duct tape

Great job. Get a cup of coffee and relax for a moment and then we'll get down to installing the electrical wire and switches for your new fan/light unit.


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