When it comes to mechanical and electrical things, noise is often an indicator that something is wrong.
If you ignore an exhaust fan's noise, you may end up with an underperforming unit, which won't remove the smells and moisture as it should be. Worse, it will continue to make irritating sounds.
Is your bathroom exhaust fan making squeaking or banging noises when you turn it on? Does it sound like it's grinding or hitting something inside? Most of the time, bathroom fan systems gather dirt, wear out the motor, and loosens up components. Thus, cleaning, adjusting, and lubricating the parts are the best ways to cut bathroom fan noise.
In this article, we're going over the main culprits of the bathroom fan noise that are ruining your peaceful life. Aside from that, we'll discuss the surefire ways fix a noisy bathroom fan.
Reasons Why Bathroom Exhaust Fan Make Noise
There will come a time when your bathroom fan will make noise due to dirt buildup, worn-out motor, or loose-fitting mounting.
Whatever the reason may be, it's wise that you know how to detect them, so that you can apply the appropriate solution.
Without further ado, let's discover how bathroom exhaust fans produce unwanted noise.
Loose or Damaged Fan Blades
The fan blades are the moving parts of the fan. It's normal to hear sounds as they spin.
Although they can be either quieter or louder depending on the quality of the components.
If you hear vibration noise, it's possible that the fan is not securely mounted.
Even brackets and mounting screws may loosen up over time, causing the blades to make noise.
Meanwhile, you may hear fast clicking or crackling sounds because of loose fan blades.
This means the blade holders are coming into contact with the motor housing.
If the fan gets loose enough, it will move inside the hole it's mounted in, causing the fan to rattle around as it operates.
When your bathroom fan is emitting repetitive knocking sounds while the blades spin, it means that it has obstructed or misaligned fan blades.
Once the fan begins to wear out and suffer from impact damage, it will make more noise as it spins.
Motor and Turbine Size
One of the most common causes of a noisy bathroom fan is the size of the fan motor and turbine.
Less expensive fans usually have high-speed fan motors yet very small turbines.
While they may move a lot of air, they can also be loud in general. On the other hand, fans with larger fan blades and more powerful motors tend to be quieter.
If your fan has only recently started making noise, it may be a sign that the motor is going bad.
Remember that the motor does all the hard work. It's responsible for turning the fan blades that move the air.
Bathroom fans will produce humming noise if they have inefficient motors. Cheap and old fans tend to have less efficient fan motors, and subsequently, louder operations.
As the motor begins to die out, the noise might turn into high-pitched whining noise.
Another common source of bathroom exhaust fan noise is the ductwork. When the fan removes the air from the bathroom, it uses a vent or ductwork to transport air outside of your home.
For this one, you can't stop moving air from creating some level of noise. You can, however, minimize the amount of noise by air moving through the ducts.
First, you must understand that higher air pressure means more noise from the air moving.
Hence, smaller diameter ducts produce more air pressure, and consequently, more noise.
This is why the quietest bathroom fans on the market tend to have six-inch ducts. The problem is that home ceilings usually have three or four-inch ducts.
If, for example, your fan features a six-inch duct, but your home has a four-inch duct, you can still use a reducer to hook the fan up.
Finally, know that it's ideal to have straight ductwork. Multiple or hard turns can increase the air pressure and the sounds.
If you live in a multi-unit building, there's a chance you'll still hear the bathroom fan buzzing even when it is off.
This is because the duct is linked to other units' fan ducts. When someone else's fan is running, the vibration moves from their fan, through their duct, and into your ductwork.
Bad Mounting or Poor Installation
If you hear vibrating noise from an exhaust fan, it's also due to poor mounting or shoddy installations.
There's also a possibility that the screws and mounting hardware are loosening up.
When the fan becomes loose, it can't contain the vibration coming from the motor and fan blades.
As a result, the whole fan assembly moves, creating excess noise in the process.
To make things worse, the vibration travels into the walls and ceiling, multiplying the amount of noise it makes.
If you hear squealing sounds from a bathroom fan, this is mainly because of moving parts that are starting to get too dry.
As the dry parts rub together at high speeds, they also create friction and noise.
Debris and Dirt Buildup
Bathroom fans emit grinding noise as the fan spins and grinds because of excessive buildup of dust, dirt, and grime.
The hard matter results in extra wear on the fan and shortens its lifespan.
Likewise, you may hear grinding or knocking sounds if the fan misalignment causes debris to get stuck inside the fan housing.
Ways on How to Fix a Noisy Bathroom Fan
After discovering the possible reasons why exhaust fans become noisy, now's the time to arm yourself with the knowledge to fix it.
From cleaning to replacing components and lubricating parts— there are several ways for you to make a noisy bathroom fan quieter.
Adjust the Fan Blades or Fan Housing
As discussed earlier, fan blades or housing that become out of whack can cause all kinds of noise.
Worse, they can suffer from great levels of wear and tear, taking years off your fan's lifespan.
To avoid this, realigning of the fan blades or housing can do the trick. First, turn the fan off before removing the fan cover.
Then, use your finger or a screwdriver to move the fan blades gently. Look for any obvious signs of problems.
If the fan blades are not moving straight or hitting the housing, you need to make some adjustments.
Remove the fan and then remount it. Make sure to reinstall the fan blades completely straight.
Replace the Blower Wheel
Spin the blower wheel by hand. If it does not spin or is rubbing against the blower housing, check for obstructions.
If there are no obstructions, yet the blower wheel doesn’t spin freely, the next step is to replace it.
The blower wheel is normally pressed on with no retainer or clip. It is slightly undersized where the motor shaft goes through, creating an interference fit.
All you have to do is pry on both sides of the wheel, and pull the blower wheel straight off.
When pushing on a new wheel, there's no need to set a screw or retainer. To be sure, check with the brand if there are specific instructions for replacing the blower wheel.
Tighten the Mounting Screws
Keep in mind that screws and mounting hardware get loose through years of operation.
To prevent mounting components from making excessive noise and vibration, there are two ways to go about tightening screws depending on the fan installation.
If the fan is installed by screws being run through the fan assembly and into a joist, you may be able to tighten them without getting into the attic.
For this one, you need to remove the fan cover, locate the screws, and tighten them.
Meanwhile, some fans use ceiling joists with hangers for mounting. In this case, head up to the attic and locate the bathroom fan from above.
Begin by tightening all of the screws that attach the fan to the hangers and joists.
Afterward, follow the hangers from the fan assembly to the nearby joists. Check the fan assembly by moving it gently with your hand.
Lubricate the Blades and Fan Motor
Even as you use bathroom exhaust fans every day, lubrication can prevent it from drying out and experiencing friction.
Turn off the fan before removing the cover. Make sure there is no dust or dirt before adding lubrication. Then, lubricate around the base of the fan blades.
Spin the blades around a few times while applying lubricant to ensure the coating gets deep into the moving parts where the friction is optimal. In this way, you can even add years to the expected lifespan of the fan.
Replace the Fan Blade
If the fan blades do not turn freely, check for any obstructions you can remove.
If the blades still don't move as they should be, it means they might be damaged, and you need to replace them.
To do this, simply follow these steps:
- Unplug the fan and turn off the bathroom's switch to guarantee your safety.
- Stand on a ladder or balanced stool to reach the fan's cover.
- Use a screwdriver or drill to remove the cover's screws. If there are no screws, push the spring inwards and pull the cover down.
- Use a screwdriver to remove the blades within the fan. Rotate the blade counterclockwise while holding the base and pull it out.
- Attach the new fan blades in the same place you took the old ones out. Fasten screws to fit it.
- Push back the cover into position or use a screwdriver if necessary.
Install a New Motor
If you see any visible signs of damage, like excessive heat damage, it's high time to get a new bathroom fan motor.
Wiggle the motor shaft back and forth to check if there are worn-out bearings.
If the motor shaft moves slightly, this means that the bathroom has defective bearings.
Unfortunately, worn-out bearings are not repairable, which means you need to replace the motor using these steps:
- 1Cut the electricity off in the bathroom.
- 2Use a screwdriver to remove the fan cover.
- 3Disconnect the motor wires.
- 4Make sure to put the right motor model and size. You can locate the model number on the bathroom fan housing.
- 5Some motors come with a mounting bracket. Loosen the screws and remove the motor assembly.
- 6Remove the old motor and the blower wheel from the bracket.
- 7Install the wheel and then align the new motor onto the bracket.
- 8Use an adjustable wrench to secure the nuts.
- 9Some motors are attached to a mounting plate. You need to remove it as one piece.
- 10Remove all screws holding the mounting plate in place.
- 11Use a flat blade screwdriver to release the tab and remove the assembly.
- 12If you're replacing the motor, unscrew the nuts and remove the mounting plate and blower wheel.
- 13Slide the blower wheel onto the new motor until it's secure.
- 14Align the motor to the bracket and tighten the nuts.
- 15Place the motor assembly back and return the cover.
Remember, the more powerful the motor, the quieter the fan becomes, and the better job of ventilating the bathroom.
By installing a new bathroom fan motor, you can save quite a bit than buying a new fan unit.
Apply a Sorbothane Rubber
If you are a soundproofing nerd like me, you've probably scoured the internet for the best vibration and noise isolating materials.
One of those is a Sorbothane rubber, which absorbs vibration and sounds.
A Sorbothane rubber comes with an adhesive backing, so that you can apply it to your bathroom fan easily.
Cut it into 1.5 to 2-inch wide strips then apply it around the fan in line with the wall or ceiling against the unit when installed.
By doing so, you can effectively decouple the fan from the wall, thereby reducing the amount of vibration and noise.
To further dampen the sounds, you can add some rubber to the electrical access plate and the fan motor assembly.
Create a Larger Duct
The larger the duct size, the less air pressure the air creates when the fan is expelling.
If you're upgrading to a larger duct because your new bathroom fan has a six-inch duct, you need to replace the existing ductwork.
On the other hand, you must get an enlarger coupling if you're keeping your old fan yet upgrading to a larger diameter duct.
For new ductwork, it's better to hire a professional, although it's good to have an idea of how the process works.
If you're installing a new duct on an existing fan, unhook the duct from the fan's outlet.
Then, install the enlarger coupling on the outlet. Remove the existing duct from the fan to the vent in the wall or roof.
Straighten Out the Ductwork
If the ductwork has many hard turns or kinks on its way to the exterior vent, it will continue to produce extra pressure, and subsequently, loud noises.
It's easier to straighten out the ductwork than replace it, although it may not have the same effect.
Regardless, it's a simple yet effective way to help reduce the air pressure and eliminate air movement noise.
First things first— go and locate the ductwork for the bathroom fan. Next, follow the duct from the fan to the exterior vent. Take note of how many hard turns are in the line.
If the ductwork needs to take a turn, you can lessen the impact by lengthening the turn.
For instance, if there's a 90-degree connector, replace it with two 45-degree connectors to reduce air pressure.
Choose a New and Quieter Fan
If component replacement or maintenance isn't working anymore, it's maybe because your bathroom fan needs to retire.
The average life of a bathroom exhaust fan is about ten years, which means there are things beyond repair.
Fortunately, investing in modern, ultra-quiet fans is cost-effective. If you decide to buy a new one, you can either hire a professional to place it, or you can do it yourself:
- 1Disconnect the power to your existing fan.
- 2Remove the screws that mount the fan to the joists.
- 3Disconnect the old duct, electrical cable, and housing.
- 4Remove the old fan and check your new fan for sizing.
- 5Install and secure the new mounting frame.
- 6Put the fan in place and screw it into the joists. This may depend on the brand, so consult the user's manual for guidance. There are models that you can screw in from the bottom, while others mount above the drywall by attaching to hangers that screw into the joists.
- 7After mounting the fan, hook it up to the duct.
- 8Slide the duct over the outlet on your fan.
- 9Use foil tape to secure the duct.
- 10Hook up the electric components. You can also hire an electrician if you have safety concerns.
Fan Cleaning and Maintenance
Like any other thing, dirt buildup is a sneaky way for bathroom fans to make noise. The dirtier the fan, the noisier, and less effective the fan.
As time goes by, all sorts of muck gather on the blades, motor, and vent. Ideally, it would be best to clean the fan every two months to keep it operating at peak performance.
Before anything else, turn off the power supply to the fan. Then, remove the vent or cover.
After doing the first two steps, only then can you do the following:
- Clean the blades, fan housing, motor assembly, and vent using a rag and warm soapy water.
- Use an old toothbrush to scrub all the dirt off the motor.
- Utilize a can of compressed air to blow out stuck dirt, then clean up any debris with a hand vacuum.
Make sure everything is dry before putting the fan cover back and turning the power back on.
If the fan is still noisy after cleaning, then it's possible that there's something wrong with the motor, blades, and mounting.
A loud, annoying bathroom fan can become a real nuisance to your home.
Before considering replacing an exhaust fan, it's important you know how to minimize or eliminate the noise. Now, make your bathroom fan quieter and your life more peaceful.
Jessica is a Acoustical Engineer, currently based in the San Francisco Bay Area in California. After graduating from her degree in Master of Engineering degree in Acoustics from Solent University in 2014, Jessica worked for a few companies before She will be blogging about her past and current experiences in the studio and sharing her journey as she pursues her career goals. She enjoy the balance of work inside and out of the office, solving practical problems on a daily basis as every project is different and requires a different solution, the variety of work (sound insulation testing, background noise survey, mechanical plant commissioning, external plant assessment, plant room breakout assessments) and the mix of independent and team work.