When installing a bathroom exhaust fan, you need to consider where the exhaust fan can most effectively fulfill its role, and where the ductwork can fit effectively. The exhaust fan’s role is to remove the humid, wet air that can cause mold to grow in your home and damage parts of your bathroom when left unventilated.
There are many types of exhaust fans and installation directions but can they be installed vertically as well?
This isn’t the only mounting option for bathroom exhaust fans, and other questions could be raised about the best positioning and location of the exhaust fan. Such as, if they can be installed on a wall, above a shower, and where best to install.
As a general rule, bathroom exhaust fans can be installed vertically/on the wall. Some of these exhaust fans even put that mounting position as an option in the manual. Though you should always consult the manual before making the decision to install it vertically, many can be installed in this position.
Can A Bathroom Exhaust Fan Be Installed on a Wall?
There are bathroom exhaust fans that can be installed on walls, like this one from amazon. However, they’re much less common than the ceiling installation models. This is partially because it is much harder to install a bathroom exhaust fan on the wall than it is through the ceiling.
- UL listed for through-the-wall application
- Includes 10-inch galvanized sleeve and steel exterior hood
- UL listed for tub/shower enclosure when GFCI protected
- This Panasonic wall mounted ventilating fan uses a propeller fan driven by a capacitor motor. The motor is designed for extended service life with reduced energy consumption. It also incorporates a...
Last update on 2023-05-29 / Affiliate links / Images from Amazon Product Advertising API
Wall-mounted exhaust fans are also much more likely to see back drafting, in addition to being harder to install. It would also help if you considered that when you have a warm/hot shower, the wet and hot air will rise, so the wall-mounted exhaust fan will have a harder time doing its job effectively than the ceiling-mounted fan.
There are pros and cons to both wall and ceiling-mounted bathroom fans.
Though it is possible to install a bathroom exhaust fan on the wall, you should install it close to the ceiling if you decide to use one.
Many exhaust fans can be used for both the ceiling and the wall, depending on the need, but not all of them. It would be best if you double-checked before purchasing if it is possible to mount the fan you have chosen on a wall.
However, it is essential to remember that exhaust fans with lights and units that have some form of a heating function should not be mounted on a wall. Walls are oftentimes much thicker than ceilings, and you should consider this while planning where the ducts will go, and where you plan for the exhaust fan to sit.

There are ductless bathroom fans that don’t come with the concern of whether or not you can get ductwork through the wall, but they do nothing for the moisture in the room.
All they do is circulate air through a carbon filter to remove odors. They won’t remove the moisture from the shower and or bath. This should be considered while looking for a wall mounting exhaust fan, but not as the only option as it serves better when paired with another form of ventilation to the room.
Can You Install an Exhaust Fan Above A Shower?
As the goal of an exhaust fan is to be as close to the humidity and moisture source, a good question to ask is whether or not you can install the exhaust fan directly above the source of the humidity and moisture. A shower can seem a bit dangerous for any product or wiring to be close to it, so what about putting an exhaust fan directly above the shower?
The simple answer is, in some cases? Yes, you can put an exhaust fan above the shower. This is entirely dependent on the type of exhaust fan that you have, but if your exhaust fan is attached to a Ground Fault Circuit Interrupter, and if it is rated for a shower area as well, then it can be placed directly above the shower.
However, you should know that not all of them can, and you need to be careful to read the manual to ensure that you don’t purchase one with a heater, for example, because they can’t go directly above the shower area safely.
Where is the Best Location for a Bathroom Fan?
The bathroom exhaust fan’s task is to exhaust moisture that is created by the shower out of the house, with the added bonus of ventilating bad odors from the room as well. This is to prevent mold, wood warping, wallpaper peeling, and other damage that the moisture can cause if left to sit in the room.
To help your bathroom fan do its job effectively, you need to find a place in the bathroom where it can easily suck out the moisture and humidity. For example;
if you have a separate bath and shower in your bathroom, you’d want to put the exhaust fan right in the middle of the two.
If you have only a bath or shower, placing it as close to or over the shower or bath is the best way to ensure that the exhaust fan can do its job most effectively. If the bath or shower is in a separate room from the main bathroom, it needs its own fan. The best way to handle this is to have two fans, one in the main bathroom with the toilet, and one in the room that the shower or bath is in as well.
Additionally, you want to plan your ductwork ahead while looking for the best place for your bathroom fan to go. You want the ducts to have the shortest, most direct route to the exterior of the home as possible. Whether it’s a roof vent or a wall vent, you want the exhaust fan to be within 6 feet of the exterior vent, if possible, to help avoid leaks and condensation build-up in the ducts.
You should also not put the fan close to an area in the bathroom that air can get into the room. For example, you shouldn’t put your exhaust fan close to a window or a door. You should also not have the vent let out the exhaust into the attic, it needs to be expelled outside of the home.
You can read my guide on how bathroom fans should be vented if you wish to learn more.
While looking for the perfect spot to install an exhaust fan, you need to ensure that you are not allowing there to be another problem elsewhere. The whole point of the exhaust fan is to avoid moisture build-up because it is much easier and less expensive to do preventative measures than it is to have to fix something after the mistake has already been made.
What Else Is Important When Installing A Bathroom Fan
While positioning the fan is important, there are other factors that should be taken into account when installing a bathroom fan.
In addition to everything below. Make sure you don’t forget to pull a permit. Or if you hire someone to install the fan make sure they do it. In most cases, contractors will pull permits.
Here is everything that must be considered
Duct size
The size of the duct is crucial for the fan to work efficiently. An undersized duct will make the fan much louder and reduce its capacity to move air.
The general recommendation is to use at least the same size duct that is on the bath fan housing connector. If the duct run is longer than 20 ft consider going up one size.
Duct Type
Rigid metal or PVC duct is preferable, If the duct run is short a flex duct can be used.
Duct routing
Find the shortest and straightest path from the fan to the termination point. The fewer turns and the shorter the duct is the more efficient the entire system will be. Often the fan is vented through the roof or wall.
Duct insulation
Also, don’t forget to place insulation above the fan housing. Find out if your fan can be covered without clearance, or it needs a box for clearance.
Fan capacity
The bathroom fan capacity is calculated according to the volume of the bathroom. I have created a bathroom fan CFM calculator you can use to find out the correct airflow.
It is important that the fan has sufficient capacity in order for it to dry the bathroom in a timely manner.

Must vent to the outdoors
The bathroom fan must ALWAYS vent outside of the building envelope. I can not stress enough how important this is.
In fact, having no bathroom fan could be better than venting it to the attic. If there is no bathroom fan the moisture damage from not having a bathroom fan will be visible in the form of growing mold in the bathroom. However, if the moist air is exhausted Into the attic or any other hidden space, the mold and mildew can grow for years without anyone noticing. This can end up costing tens of thousands to clean up.
Conclusion
Bathroom exhaust fans are an essential aspect of the ventilation of the humidity in the bathroom. Ensuring that you are installing your bathroom vent properly is the best way to be confident that you are taking the correct measures in preventing the growth of mold. The damage that can be done to a poorly ventilated bathroom is often expensive and potentially a health hazard as well.
An important tip is to make sure that you consult your community regulations when it comes to bathroom ventilation, as it varies from community to community so dramatically. Whether you choose to install it on the wall, above the shower, or elsewhere you need to ensure that your bathroom ventilation is up to your community code.
Finally, ensure that you have read the manual for the specific type of bathroom exhaust fan you are considering purchasing before you install it. This helps you avoid making unfixable mistakes or damaging the exhaust fan through misusing it.