How to Check and Fix Your Bathroom Exhaust Fan

A bathroom exhaust fan is a device that helps to remove moisture, odors, and pollutants from the bathroom. It also helps to prevent mold, mildew, and damage to the walls and ceiling. A bathroom exhaust fan is usually installed in the ceiling or wall near the shower or bathtub, and it vents the air outside through a duct. However, a bathroom exhaust fan can sometimes malfunction or become noisy, dirty, or inefficient.

This article will show how to check and fix your bathroom exhaust fan using simple tools and techniques. You will learn how to inspect the fan, clean the blades and grille, replace the motor or switch, and test the airflow.

Following these steps, you can ensure your bathroom exhaust fan works properly and efficiently.

How to Check Your Bathroom Exhaust Fan

The first step is checking if your bathroom exhaust fan works properly. Two simple methods exist to do this: the toilet paper test and the gap under the door test.

The Toilet Paper Test

The toilet paper test is the most common way to check your fan’s suction power. You turn on the fan and hold a toilet paper or paper towel over the fan grille. If the paper sticks to the grille, the fan is sucking air. If not, it means the fan is not working properly.

The Gap Under the Door Test

Another way to check your fan’s airflow is to look at the gap under the bathroom door. The fan should pull air from under the door and create a slight vacuum in the bathroom. You can test this by placing a strip of toilet paper along the gap and see if it moves away from the door when the fan is on.

Suppose your fan passes both tests; congratulations! You have a working bathroom exhaust fan. If not, don’t worry. We will discuss some possible causes and solutions in the next section.

How to Troubleshoot Your Bathroom Exhaust Fan

If your fan is not working, there could be several reasons. Some of the possible causes are:

• Dust buildup on the fan cover, grille, or motor
• Obstruction in the duct or exterior hood
• Improper connection of the duct to a roof or soffit vent
• Insufficient gap under the door or lack of supply air register
• Wrong size or rating of the fan for the bathroom

Here are some possible solutions for each cause:

Cause	Solution
Dust buildup	Insufficient gap or supply of air
Obstruction	Remove any obstruction in the duct or vent, such as debris, bird nests, insects, etc.
Improper connection	Clean the fan cover, grille, motor, and duct with a vacuum cleaner or a damp cloth.
Increase the gap under the door by trimming it or adding a vent grille; add a supply air register in the bathroom ceiling or wall.	Upgrade or replace the fan with a higher CFM (cubic feet per minute) rating that matches the size and humidity level of your bathroom.
Wrong size or rating	Upgrade or replace the fan with a higher CFM (cubic feet per minute) rating that matches your bathroom’s size and humidity level.

To diagnose and fix each problem, you may need some tools and materials, such as:

• Screwdriver
• Vacuum cleaner
• Damp cloth
• Duct tape
• Wire cutter
• Wire nuts
• New duct or vent
• New fan

Some of these tasks may require professional assistance or electrical knowledge. If you are unsure how to do them safely and correctly, please consult an expert or hire a qualified contractor.

How to Repair or Replace Your Bathroom Exhaust Fan

Sometimes, cleaning and troubleshooting may not be enough to fix your fan. You may need to repair or replace some parts or even install a new one. Here are some signs that indicate that you need to repair or replace your fan:

• The fan makes loud or unusual noises
• The fan vibrates excessively
• The fan runs slowly or intermittently
• The fan does not turn on or off
• The fan does not reduce the humidity or odor in the bathroom.

Repair or replace the bathroom exhaust fan

For bathroom fan repair or replacement, follow these steps:

1. Turn off the power to the fan at the circuit breaker or fuse box.
2. Remove the fan cover and grille by unscrewing or unclipping them.
3. Disconnect the fan motor from the housing by unplugging or cutting the wires.
4. Remove the fan motor and blade from the housing by unscrewing or unclipping them.
5. Inspect the fan motor and blade for any damage or wear.
6. If the fan motor or blade is damaged or worn, replace them with new ones that match the specifications of your fan.
7. If the fan housing or duct is damaged or worn, replace them with new ones that fit your bathroom and vent.
8. Reconnect the fan motor to the housing by plugging or splicing the wires with wire nuts.
9. Reattach the fan motor and blade to the housing by screwing or clipping them.
10. Reinstall the fan cover and grille by screwing or clipping them.
11. Turn on the power to the fan and test it.

If you are installing a new fan, you will need to follow these steps:

1. Turn off the power to the old fan at the circuit breaker or fuse box
2. Remove the old fan by following steps 2 to 4 above.
3. Measure the size of the old fan housing and duct and compare it with the new one.
4. If the new fan housing and duct are smaller than the old ones, you may need to adjust the opening in the ceiling or wall with a saw or a drywall knife.
5. If the new fan housing and duct are larger than the old ones, you may need to enlarge the opening in the ceiling or wall with a saw or a drywall knife.
6. Install the new fan following steps 8 to 11 above.

Choosing the appropriate fan size and rating for your bathroom:

To choose the right size and rating of a fan for your bathroom, you will need to consider these factors:

• The size of your bathroom in square feet
• The humidity level of your bathroom (low, medium, or high)
• The type of fixtures in your bathroom (shower, tub, spa, etc.)
• The length and diameter of your duct and vent

A general rule of thumb is to multiply the square footage of your bathroom by 1.1 for low humidity, 1.35 for medium humidity, and 1.5 for high humidity. This will give you the minimum CFM rating you need for your fan. For example, if your bathroom is 100 square feet and has medium humidity, you need a fan with at least 135 CFM.

However, this is only a rough estimate. You may need to adjust it depending on other factors, such as:

• The number of elbows or bends in your duct
• The distance between your fan and vent
• The type and size of your vent (roof or soffit)
• The presence of other sources of ventilation (windows or doors)

How to Clean and Maintain Your Bathroom Exhaust Fan

Once you have checked, fixed, or replaced your fan, you must clean and maintain it regularly to keep it in good condition.

Here are some tips and suggestions on how to do that:

• Clean your fan cover, grille, motor, and duct at least once every six months or more often if you notice dust buildup or reduced airflow
• Use a vacuum cleaner with a brush attachment to remove dust from the cover, grille, motor, and duct; use a damp cloth to wipe off dirt or grease.
• Do not use harsh chemicals or abrasive materials that may damage your fan; use mild soap and water if needed.
• Do not spray water directly into your fan; this may cause electrical shock or damage your fan.
• Check your duct and vent for any obstruction or leakage; remove any obstruction and seal any leakage with duct tape or caulk.
• Check your vent for any backdrafts; ensure it has a damper or flap that closes when the fan is off.
• Check your gap under the door or supply air register for adequate airflow; ensure rugs, furniture, etc, do not block them.
• Check your fan’s performance and noise level; if you notice any decline or increase, you may need to clean, repair, or replace your fan.

These tips and suggestions can keep your bathroom exhaust fan clean and efficient.

Conclusion

A bathroom exhaust fan is essential for ventilation, moisture control, odor removal, and mold prevention. It can also improve your indoor air quality and comfort.

However, not all bathroom exhaust fans are created equal. Some may not be powerful enough, some may be too noisy, some may be clogged with dust, and some may not even work.

FAQ

Resources

• Home Inspector Secrets.
• Air King Limited.