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Installing a bathroom vent can be the solution needed for your spaces, which never seem to dry. The air, when laden with moisture in the bathroom, becomes the enemy for the bathroom paint, the window sills, and fabric items like curtains and towels as well.
Eliminating the moisture and odors from the bathroom makes it a much better experience for all and gives it a much better outlook.
Now the question arises, how to install a bathroom exhaust fan through a wall? This may not be the easiest home improvement task, as a significant portion of this task revolves around the physical effort of standing on the ladder and working on the wall.
How to Install a Bathroom Exhaust Fan?
Before you Start
There are two concerns that most homeowners have before they start this project, i.e., venting outside the house and power supply.
Most bathroom fans used in homes require AC 120V electric lines. These instructions offer tips to look for live electrical wires and running them to the appropriate location.
The vent is a system that draws air from the bathroom and blows it out of the house. This is a new installation and not a replacement; ducting would not be present in your bathroom.
However, as long as the attic is accessible, the flexible tubing can be routed outside easily.
How to vent a bathroom fan?
Establish your Power Source
You are installing the bathroom vent through a wall, where a power source may already be present.
Depending on the electrical code of your area, your bathroom lighting circuit may also be shareable with the vent, as the power supply to bathroom ceiling light is usually from the bathroom lighting circuit.
If your local code requires you to run a dedicated circuit for the fan, a new cable can be taken from the service panel to the bathroom wall.
However, if you do not wish to establish such new circuits, you can get a new line from the service panel to your bathroom wall.
Locate the Vent Point

Venting a bathroom fan starts with locating the vent point. The air which is exhausted by the fan must exit outside, so a duct is also needed, running from the fan to the wall or ceiling.
A flexible ducting at the sidewall is preferred as shingle work, and any chance of roof leakage can be avoided.
To choose a vent location, the rule of thumb is to select a location which is:
- Six feet or less from the exit point to the bathroom.
- Straight route from outdoor to the fan. Make sure to have a safe location for outdoor vent to keep ants away from bathroom.
- Inside the bathroom, instead of a corridor or hallway.
- Located close to tub, shower or a combination of the two, as these areas produce the most moisture.
- Avoid sharp ends which can intervene airflow by choosing a route as straight as possible.
Cut the Exterior Vent Location
According to the location you intend to exhaust the outside, access either the roof of the house of the sidewall.
Bring a vent cap (in case of the roof) or around the vent (for walls), along with cordless drill, reciprocating saw, silicone caulk, and pencil.
Locate the round vent cap across the locator hole. The locator hole shall be created first wherever you intend to locate the outside vent.
Using the reciprocating saw, cut the circle by using the locator hole as the starting point for the saw blade. Now attach the round vent using screws; before this, apply silicone caulk, ensuring a watertight fit.
Cut the Interior Opening for the Bathroom Fan
Use the stud finder form below to locate the spars in the bathroom wall and mark them lightly with a pencil.
If a template is included in your vent, the model can be used to mark the location intended for the fan on the wall. However, if no model is included, use the metal vent housing itself, leaving the fan assembly alone for the time being.
There are direct screws to the side of the joist in many bathroom vents already. In such a case, the housing or template shall be placed parallel to a beam when creating the cut lines. The drywall should now be cut carefully using a jab saw.
Attach the Bathroom Fan to the Joist
Access the wall and bring up your cordless drill, light, screws, and bathroom vent housing. The fan should be placed in the cut-out hole, so the fan’s bottom edge is flush with the drywall’s bottom part.
A partner’s help may be needed for this step as it is difficult to see the wall from this position. Now screw the fan into the sides of joists using a cordless drill.
If a joist’s side can not be used as an attachment point, suspension brackets may also be included with the vent. If these are not included, you can easily purchase them separately as well.
The fan will be allowed to be suspended in a position that is not adjacent to the joist by the brackets.
While you are still standing at the wall, fit the electrical wire from the side of the housing so that around seven inches of the cable is extending into the housing.
Route the Bathroom Fan to the Exterior
Get down and verify the placement of the fan is vertical. Collect your flexible ducting and go back to the wall with it.
Now attach this flexible ducting to the vent and fan. Make sure that the tubing is running as directly and smoothly as possible, without any sharp ends.
Attach the Bathroom Fan to the Housing
Insert the fan unit in the housing inside the bathroom, using the instructions of the manufacturer. You shall now strip the electrical wires’ ends and hardwire them in the group.
Usually, a green or bare wire will be attached to the metal housing’s side for earthing, which a safety measure.
Now attach the fan grill to its housing. Please turn on the circuit breaker back, and return to the bathroom to test your fan by switching it on.
By now, you must be able to understand how to install a bathroom vent through a wall and must now be planning to take up this project. So, go ahead, get your supplies, and start over!