How to Choose and Install Wall-Mounted Bathroom Exhaust Fans

When you step into your bathroom, you should always be able to feel the comfort and cleanliness of the space. That’s why finding the right wall-mounted exhaust fan matters so much — it keeps the bathroom free from excess humidity, odors, and unhealthy air. 

However, choosing an ideal wall-mounted bathroom exhaust fan for your bathroom isn’t as straightforward as it may seem. Usually, it depends on numerous factors, such as the size of your space, the fan’s ventilation capacity, noise levels, or the correct CFM rating. 

In this article, we’ve gathered all the essential tips and insights you need to know about wall-mounted bathroom exhaust fans. 

What is a Wall-Mounted Bathroom Exhaust Fan?

A  bathroom exhaust fan is a ventilation device installed on the wall that is frequently used in areas such as bathrooms or kitchens. The purpose of this device is to remove excess moisture, odors, and stale air from your room and direct it outside. People usually use these devices in areas where ceiling installation isn’t an option as a result of a limited roof cavity.

The main reason why wall-mounted bathroom exhaust fans are so convenient is that they prevent the buildup of mold through proper ventilation. Therefore, they can help you keep your environment fresh, healthy, and comfortable.

A typical wall-mounted bathroom exhaust fan consists of several components:

  • Motor component – Powers the unit to draw air from the bathroom.

  • Ducting or tubing – Channels the extracted air from the bathroom to the outside.

  • External vent – The outlet for the air that directs moisture and odors outdoors.

Types of Bathroom Exhaust Fans

Before upgrading your bathroom’s ventilation system, you need to understand the different types of bathroom exhaust fans to determine whether a wall-mounted type is suitable for your bathroom. Here are the 4 most common types of bathroom exhaust fans:

  • Wall-mounted fans –  Typical used when a ceiling mount isn’t practical or has limited roof space. They’re installed directly into the wall and vent outside.

  • Ceiling-mounted fans – These are installed into the ceiling and vent through the roof or an exterior wall. They’re common in most residential bathrooms.

  • Inline fans – They’re installed in a remote area and, therefore, aren’t directly visible in the bathroom. Thus, this type is perfect for larger bathrooms or when you want to keep the fan itself out of sight

  • Combination units – These fans offer more than just ventilation. In fact, they come with built-in lights, heaters, or even Bluetooth speakers.

Choosing Your Wall-Mounted Fan

After exploring the various types of bathroom exhaust fans, if you’ve decided a wall-mounted fan is the right choice for your bathroom, now it’s time to learn how to choose your wall-mounted fan. 

In general, wall-mounted fans come with a few key features. In order to choose the most suitable one for your bathroom, look out for the following factors:

Location of the Fan

The first and perhaps most important thing you should consider is choosing the right location for your wall-mounted bathroom fan. The rule of thumb here is to locate it in a place where it can extract moisture and odors most effectively. Typically, it’s opposite the room’s entry or near the shower.

Size and CFM of Your Bathroom

The size of your bathroom directly affects the effectiveness of the exhaust fan you get. The thing is that the fan can only produce sufficient airflow if it fits the room. One important measurement you should have in mind here is CFM – cubic feet per minute.

CFM is a measure of how much air the fan can move each minute. Usually, larger rooms require exhaust fans with higher CFM. 

How can you determine the CFM for your room?

  1. Calculate the volume of your space (length x width x height)

  2. Determine your desired ACH (decide on the number of air changes per hour you want). Note that bathrooms typically benefit from 6-8 ACH for effective moisture and odor control.

  3. Multiply the volume of your space by the desired ACH

  4. Divide this number by 60 (the number of minutes in an hour) to convert it to CFM

Here’s a clear example of this simple calculation:

  • If your bathroom measures 10 feet long, 5 feet wide, and 8 feet high, the volume is 400 cubic feet (10 x 5 x 8).

  • For a goal of 8 ACH: 400 cubic feet (volume) x 8 (ACH) = 3200.

  • Then, divide by 60 to find the CFM: 3200 / 60 = approximately 53 CFM.

Therefore, in this case, you need an exhaust fan with at least 53 CFM to achieve 8 air changes per hour in a 400-cubic-foot bathroom.

Noise Level

The noise level of a bathroom exhaust fan is another important thing you should keep in mind while choosing a wall-mounted fan. Fan noise is measured in sones. In general, a lower Sone rating means a quieter fan. We recommend considering how the fan’s noise will affect your bathroom’s ambiance and choosing the device accordingly.

Energy Efficiency

Look for fans with ENERGY STAR® ratings. It’s a government-backed symbol for energy efficiency that can help you save on electricity costs without sacrificing performance. This rating is based on a star system where 5 means the most efficient and 1 is the least efficient.

Speed Control

Bathroom exhaust fans that feature a speed control function allow you to adjust the fan’s operation based on your current needs. In particular, speed control helps you manage ventilation more easily. For example, a fan that includes speed control can increase the speed for rapid removal of humidity after a hot shower, or lower it to maintain air quality without excessive cooling.

Additional Features

Finally, don’t forget to consider some additional features as well that aren’t always necessary but can add some value and enhance functionality to your bathroom exhaust fan.

Here’s a short list of some extra features to look out for:

  • Built-in lights

  • Humidity sensors

  • Motion sensors

  • Heaters

  • Timers

How to Install a Wall-Mounted Bathroom Exhaust Fan

Now, let’s see how you can install a wall-mounted exhaust fan in your bathroom. It doesn’t matter whether you’re going to do it by yourself or hire a professional, there are a few things you should keep in mind before the installation process takes place. 

Here’s a simple step-by-step guide to installing a wall-mounted bathroom exhaust fan:

Step 1: Plan and Prepare

The first step before installing a wall-mounted fan is to consult your contractor. That’s the most effective way to ensure your new fan meets local code requirements and will pass inspection. 

Here are some key things you should take care of initially:

  • Code compliance – The fan must have a humidity sensor to effectively manage moisture levels and pass inspection.

  • Bathroom size – Measure your bathroom to determine the needed CFM for effective ventilation. For example, you might have a huge bathroom for which a standard exhaust fan won’t be suitable. 

  • Right location – Ideal placement of the fan is above the toilet and outside the shower pan for longevity and efficiency (note that it should be close to the shower pan, but outside).

  • Number of fans – In order to meet the code, sometimes you may need to install two fans instead of one fan. For instance, if you have a master bathroom that features a small toilet room inside, by code you’re required to install two fens.

  • Ensure symmetry and aesthetic integration in the bathroom layout.

  • Installation considerations – The fan should connect to an exterior vent, with roof patching and flashing installed for waterproofing.

Step 2: Mark and Cut the Vent Hole 

After planning, you should determine where your vent hole will be. For this, we suggest finding a spot outside of your house that aligns with the fan’s location inside. Draw a mark and drill a hole. Note that you should choose the right size hole saw based on the duct size that’s usually recommended by your fan’s manufacturer.

Once you drill the pilot hole from the outside, you’ll have a clear marker for where to cut from the inside. If necessary, use a jigsaw or keyhole saw to enlarge this initial hole.

Step 3: Install the Fan Housing

Once your vent hole cut is done, you should focus on installing the fan housing inside the bathroom. Try to position the housing against the interior wall and align it with the vent hole you’ve just created. With a pencil, mark the screw holes on the wall. Then, remove the housing and drill pilot holes at these marks.

After you drill the pilot holes, hold the fan housing in place and fasten it securely to the wall using screws. For the best support, try to anchor the housing into studs. 

Note that if the location doesn’t allow for direct stud mounting, you may need to use heavy-duty wall anchors designed for your type of wall material. 

Step 4: Attach the Duct and Make Electrical Connections

Now, connect the fan to the external vent using ductwork. Ideally, you should use moisture-resistant seals with foil, duct tape, or a metal clamp. That’s how you can prevent air leaks and moisture in the future. For example, if your fan has a 4-inch port, use a 4-inch duct.  It’s also important to maintain as straight a duct path as possible to the outdoors to optimize fan performance.

The next step is to focus on the electrical connections. Turn off the power at the breaker box to ensure safety. Follow the fan’s wiring diagram to connect the wires correctly — usually, this involves matching the color-coded wires (black to black for power, white to white for neutral, and green to ground) and securing them with wire nuts. 

Don’t forget to wrap the connections with electrical tape for extra safety. And that’s all you need to get ready for the final assembly and testing of the fan.

Step 5: Attach Covers and Seal

Now you’re ready to attach the fan’s interior cover by snapping or screwing it into place. Outside, secure the exterior vent cover to protect against weather and debris. Seal both covers with silicone caulk to prevent air leaks and moisture entry. After installation, test the fan for smooth operation by turning the power back on.

Care and Maintenance for Your Bathroom Exhaust Fan

Now you already have enough information about wall-mounted bathroom exhaust fans to make an informed decision and ensure proper installation. The final thing that is left is maintenance. 

Keeping your exhaust fan in good condition is essential for its longevity and effectiveness. To ensure its longevity, clean the fan regularly. But the most important thing is not to forget to remove dust and mold from the fan blades and housing. As an extra tip, we also suggest monitoring any changes in noise level or performance, as it might indicate a problem. And if that’s the case, don’t hesitate to seek professional help for repairs or replacements. 

Our team at Prada Builders in San Jose is ready to assist with any maintenance needs or concerns you may have. Get in touch with us, book your consultation, and ensure the longevity and effectiveness of your bathroom’s ventilation system.

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