Why Bathroom Fan Making Noise When Windy?

Bathroom vents can become notoriously noisy when it gets windy, making your home sound like a horror movie. If this banging sound doesn’t seem to go away, there’s a way to fix it. You won’t have to wake up in the middle of the night wondering if someone has broken into your house.

Your bathroom fan makes noise when it’s windy because its flapper gets raised by the wind, then drops down, producing the banging noise. Wind on the outside causes the air pressure to drop, sucking out the high-pressure air inside the house through the exhaust duct. This airflow raises the flapper.

In this article, I’ll explain why your bathroom fan makes noise when it’s windy. I’ll also give you practical tips to fix the loud sounds. Read on.

Reasons Why Your Bathroom Fan Makes Noise When It’s Windy

The bathroom fan’s primary purpose is ventilation. Although some homeowners or builders install ductwork in their houses, they also install a vent in the ductwork to improve ventilation.

You’ll likely find vents in the bathroom, kitchen, or storage spaces. House vents may or may not come with exhaust fans. However, most of them come with metal flappers, also called backdraft dampers, on the outside that fly open to release hot air from inside the house.

Below are some of the reasons behind your noisy bathroom fan.

Pressure Imbalance Between the Inside and the Outside

Unfortunately, vent flappers produce a banging noise when the air is windy. When the wind blows, the air pressure on the outside drops relative to the air pressure on the inside. The high air pressure forces the flappers to fly open, falling when the pressure equalizes. When they drop, they clash with the vent’s metal frame producing an unpleasant noise.

On windy days, the noise becomes increasingly frequent and unbearable. But there are ways to fix the noise. And you won’t even have to replace the entire bathroom fan.

Read: Attic Fan Vs. Whole House Fan

Low-Quality Fan

The unpleasant noise from your bathroom fan might not be because of a faulty mechanism but rather due to a low-quality product. It’s worth spending a few extra bucks on a bathroom fan. The fan ventilates your bathroom by getting rid of clammy and unclean air. After a steamy shower, the fan extracts the high humidity, preventing mold development and water damage.

Therefore, you shouldn’t just buy any products out there. You need to make a careful selection. A general rule of thumb is that a cheap bathroom fan will make the loudest noise. This will become worse when it becomes windy. What’s more, it won’t thoroughly ventilate your bathroom.

Inadequate Fan Maintenance

Dirt build-up is another cause of noisy bathroom fans. Dirt and muck accumulate on the fan’s blades, motor, and vent, causing them to clog. When the wind blows, sucking out the warm air inside, the dirt on the duct walls causes irregular airflow, which causes the fan to become noisy.

Eventually, the fun produces buzzing, grinding, and whirring sounds and becomes less effective.

Read: How To Fix A Noisy Bathroom Fan?

Incorrect Fan Installation

Your bathroom fan can become noisy if you install it incorrectly. It can make strange noises if its housing isn’t securely fixed in the ceiling. The whole unit will become shaky when you turn on the fan or wind blows.

Also, as you use the fan over time, its different parts and panels may become loose and out of alignment. As the entire unit loosens up, the fan’s blades might begin hitting the surrounding housing, producing knocking, vibrating, and rattling noises.

Read: 3 Reasons Why Water Is Dripping From The Bathroom Fan

A Faulty Motor

Irrespective of the type of bathroom fan you have, its motor will require lubrication for smooth and quiet operation. Lack of lubrication can cause some motor parts to overheat and wear out, producing squeaking sounds as they grind past each other.

Some recent fan models have thermal cut-off fuses that disconnect them from the power supply in case they overheat—either way, you need to lubricate them from time to time.

How To Fix a Noisy Bathroom Fan?

Knowing what’s causing a noisy bathroom fan is the first step towards finding a solution. However, you need to have the right gear and also take proper precaution before heading to the attic to fix a noisy fan. 

These are some of the ways you can correct your noisy bathroom fan.

Soundproof Your Vent Flappers

You can use waterproof foam tape to reduce the sound from the impact between the flappers and the vent’s frame.

I recommend this HushMat HSM30300 Quiet Tape (available on Amazon.com). It adheres to metal, plastic, and fiberglass surfaces.

Once you get the tape, apply it to the edges of the flappers. Ensure it adheres properly where the flappers hit the vent’s frame. This technique should reduce the noise emanating from the metal clashes and is one of the cheapest and easiest ways to fix a noisy bathroom fan.

Add Weight to the Flappers

Adding weight to the vent flappers will make it difficult for the wind to lift them easily. However, you shouldn’t make them too heavy if you want your vent to still work correctly.

It’s best to use wheel weights with strong adhesives to adhere to the flappers. The weights should resist the frequent lifting by the wind and still let the vent operate effectively.

You can start with a ¼ oz (7.1g) wheel weight and see if the banging noise disappears. Add more weights if the flappers still bang.

Read: How To Save Heat In An Apartment?

Replace the Vent Damper

Replacing the vent damper is a long-term solution for noisy bathroom fans. When you turn off the burner, the vent damper automatically shuts off the airflow pipe.

Replace your regular damper with a spring-loaded backdraft damper. It comes with a rubber gasket that creates an airtight seal with the flapper. The seal stops unwanted airflow into the vent when the flapper is down and prevents it from banging on the frame. It also prevents air leakages.

It would be best if you had these tools to replace your regular damper with a spring-loaded one.

  • Knife
  • Caulking gun
  • Roof sealer
  • A new spring-loaded damper

How to Replace Your Vent Damper

  1. Remove the worn-out damper. Use a screwdriver to unscrew the vent tube. Follow this by cutting off any sealants with a utility knife, then remove the screws to detach the vent from the wall.
  2. Place the new spring-loaded damper into position. Remove the old damper and put the new one into position. The new damper should fit perfectly on the vent. Replace the shingles, screw them tightly, and seal any gaps around the vent edges with a caulking gun.
  3. Link up the vent tube. Screw the vent tightly to see if the flappers make the same noises as before. However, wait until it’s windy to make a good observation. This should permanently fix noisy bathroom vents.

Thoroughly Clean Your Fan and the Vent

Don’t use compressed air to clean your bathroom fan. Instead, follow these steps to clean a dirty fan.

  1. Turn off the fan.
  2. Unscrew the vent cover.
  3. Use warm soapy water to clean the fan blades and the vent thoroughly.
  4. Use a cleaning brush or an old toothbrush to scrub off any dirt on the motor.
  5. Make sure everything is dry before assembling the fan back together.

The fan should be quieter after you put everything back together. The motor might be to blame if the noise doesn’t go away. However, cleaning your bathroom fan is necessary even if it doesn’t produce any noise. It’s a way to extend its useful life.

Install a Larger Duct

A larger duct will reduce the pressure of the air extracted by the fan, thereby lessening the noise.

Newer fans come with 6-inch (150mm) ducts that help to minimize the noise. Therefore, you can upgrade your ductwork to fit the 6-inch (150mm) fans.

Straighten Your Ductwork

Dents and bends within your ductwork can cause eddies and friction in the airflow, which might make your fan noisy. Straightening your existing ductwork is cheaper and less invasive than replacing it.

Although a temporary solution, this can help reduce the air pressure and noise from airflow. Replacing the ducts with bigger and stronger ducts is a more permanent solution.

Read: Why Is Indoor Air Quality Important?

Conclusion

A noisy bathroom fan can be a nuisance to an otherwise quiet and serene home. If your bathroom fan becomes noisy when the wind blows, it is because of the flappers banging on the vent frame. It can also become noisy because of lack of lubrication on the motor and constricted vents.

Identify why your bathroom fan is noisy and use the above tips to fix it.