Exhaust fan in a bathroom wall

How to Vent a Bathroom Fan Through the Wall

You should appropriately vent your bathroom. Proper ventilation means that you will get rid of fogged-up mirrors and windows as well as any unpleasant and stale odors.

More importantly, when you get rid of the moist air in your bathroom, you are improving the overall air quality of your home. Simultaneously you are eliminating the leading cause of many moisture-related problems such as the growth of mold and mildew.

Mold doesn’t just look bad – it can also worsen the structural integrity of your home and be a significant contributing factor to many health issues. That is why you must make sure that your bathroom is properly ventilated.

Keep reading if you want to learn how to vent a bathroom through the wall. You can hire professionals to do this job for you but know that this is not too difficult of a project – if you have any experience with home maintenance, you will be done in just a few hours while the less experienced folks can get the task done in a weekend.

Either way, you will need the proper knowledge and tools to tackle this endeavor, and this article is there to teach you all there is to know about how to vent a bathroom through the wall.


Types of Fans You Can Use

Exhaust fan showcase

If you want to install your bathroom fan vertically on a wall, you will get a so-called “low-profile” bathroom exhaust fan. As its name suggests, this type of fan has a low profile, making them ideal for such an installation. In addition, these fans are perfect if you want to lead the air from your bathroom to the outside directly.

Among other bathroom exhaust venting options are through-the-wall exhaust fans. These fans are used elsewhere throughout the souse in garages, kitchens, workshops, and so on. Even though they are not made exclusively for bathrooms, they are highly versatile and quite easy to install.  For recommendations, check out our post on the best bathroom exhaust fans with Bluetooth speakers and the best bathroom exhaust fan for a small bathroom. If you don’t like noise, we also have a post on the quietest exhaust fans.


Before you can start installing your bathroom fan, make sure you have the proper tools for the job. You will need a measuring tape, duct tape, a reciprocating saw, a flashlight, marker, and a hammer. Of course, you must get a bathroom fan and the proper exhaust duct as well. Ideally, you will want to have some silicone caulking as well.

Before you start poking a hole in your wall, make sure that you know where water pipes and electrical lines are. You don’t want to cause significant damage or risk bodily harm when doing a task as simple as installing a bathroom vent.

When it comes to choosing the right place for your fan, try to keep it far from faucets and showers, and any other source of water. Most modern-day bathroom fans are water-resistant, but it is better to be safe than sorry.

Once you have found that perfect spot, take a marker and mark a reference spot where you want your fan to be.

Measuring and Making a Hole

Measuring tape on a table

For your next step, first, accurately measure the fan. Most fans are square in shape, but some are rectangular even though they don’t appear so at a glance. So measure all sides carefully and write the numbers down.

Next, get back to that perfect spot you have previously selected and grab your marker. Use the market and scale to draw the shape on the wall. Lay down those marks deeply so you can easily follow them when making the hole.

The next step is extremely important. It is time to make that perfect hole. Again, a battery-operated reciprocating saw is an ideal tool for the job. Grab it and wait a bit for the saw to reach its maximum speed before you start cutting.

Next, you will want to start making the hole. All you have to do is guide the saw exactly over the marked line. Keep it nice and steady, and don’t rush this part of the task. You will most likely have to make several passes with the saw before the hole is complete, so pace yourself and don’t worry too much if the gap doesn’t look perfect when you start working. There will be enough time to sort things out as you move along.

A regular saw should be enough for the job if your wall is made of vinyl or fiber cement. However, if your wall is made of brick, the task will be more challenging to pull off. You will need a diamond hole saw for cutting your hole as this type of saw is much more difficult.

Cleaning and Preparation

While you are cutting the hole, some debris and remains of wood or wall might end up in your way. Simply use your hammer and pliers to clean the spot the best you can.

Before you begin installing the fan, your newly made hole must be as clean as possible.

Once you have created that ideal opening in the wall, remember to grab a vacuum cleaner and a broom and wipe clean the inside of your home. This is the least exciting part of the job, but it is better to complete it sooner than later. There will be more remains and dirt to clean down the road, so you should keep your working area as clean as possible during every step of the process.

Check out this post if your bathroom exhaust fan is leaking when it rains.

Connecting the Exhaust Duct

Exhaust duct on an exterior wall

With everything nice and clean, it is time to move on to the main event – you are ready to connect the exhaust duck and attach the fan.

For your project, you should ideally get a bath fan ducting kit. This is a set that contains everything you need. It comes with a flexible vent hose, clamps, a rigid metal pipe adapter, and an exterior vent hood with louvers.

For the time being, focus your attention on the pipes. The small rigid metal pipe should go through the wall, and the flexible hose should attach to it. The exterior part also connects to the solid metal part – under no circumstances do you want the hose part to go through the wall.

Exterior Works

You will have the exterior fan cover with the hood on the outside. If you have silicone caulking, it would be wise to use it to seal the external lid right away. If not, simply remember to do it before the rain starts, as it is supposed to stop air leaking and prevent the rainwater from falling in.

If you have the bath fan ducting kit, it should also come with a hood cover that is also used to protect the exterior of your bathroom fan from the elements. Install this bit.

Some sets also come with a birdcage or some other type of protection meant to prevent birds and rodents, and small animals from getting into your bathroom from the outside world. Follow the instructions and set this piece up accordingly.

Installing the Fan

Before you commit to attaching the fan, you should first connect it to a power source to make sure that it is in the correct working order. Now is also the right time to unfasten all of its wirings.

Next, place the fan on the fan housing – make sure that it is located right in the middle. If everything looks good, take the fan out of the carrier and securely connect the cable connection.

Once again – for the last time – place the fan into the opening and use the provided screws to lock it into position securely.

Ensure that you have fastened all the screws and connected all the wires securely. This is crucial for your safety and the future functionality of your bathroom fan. If you are not sure about the wiring and working with electricity is not something that you are comfortable with, hire an electrician for this portion of the job. While we are on the topic of electricity, check out how much electricity a bathroom fan uses.

If you have followed this guide carefully, congrats – your bathroom fan is all set up and ready to use!

If you are remodeling your bathroom, check out our post on how to remove an old tub as well.

Some Final Advice

Fan in wall

Use safety gear while you are installing your bathroom wall. Pick a nice and sunny day to do this project. Use good quality ladders to reach the high places.

Turn off the power to the bathroom before you start messing with the wires. Also, stop the water connection to the toilet just to avoid any unpleasant surprises.

Whatever you do, do not lead your bathroom vents into the attic. Not only is this practice against codes and regulations, but it is also bad both for you and your home.

Moisture in the attic space may lead to mold forming and even cause wood to rot. Such an environment is perfect for mold damage and wood decay and attracts insects. This approach will also drive your energy bill up as the hot and moist bathroom air will remain trapped inside your home and make it warmer.

Finally, mold can cause severe respiratory issues and other health problems for you and other residents of your home. Your best course of action would be to obtain one of the aforementioned ducting kits and drive the wet bathroom air away from your attic.

You may want to check out our post on how to vent a bathroom fan through soffit and our post on how to install a bathroom exhaust fan rooftop vent as well.

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