How to Fix a Noisy Bathroom Fan (Addressing Irregular Sounds)

Like any of your other household appliances, your bathroom fan is bound to get dirty or bent in ways that might disrupt its performance. If that were to happen to one of your regular room fans, buying a new one wouldn’t be the first solution you thought of. Rather, you’d probably make an effort to address the underlying issue! With that in mind, we’re going to talk about how to fix a noisy bathroom fan.

Obviously, the idea is to find the cause of the noise and address it before the fan components become irreparably damaged. But to get to that point, you first have to know the baseline noise you should expect to hear from your bathroom exhaust.

Fixing a noisy bathroom fan.

Are Bathroom Fans Supposed to Be Loud?

If you complained to a friend or family member about the level of noise your bathroom fan was producing, they might claim that you were exaggerating the issue. After all, aren’t bathroom fans supposed to be loud? That’s how you know they’re working!

Well, that’s not quite the case. Ideally, most of your household appliances should do their jobs without being seen or heard. So naturally, that goes for bathroom exhaust fans too.

How Loud Should a Bathroom Fan Be?

At most, these devices should be making about 30 decibels of noise. That means they should be nearly imperceptible! However, when you look up the bathroom fan model you have, you’ll likely see that number expressed in another measurement.

Namely, exhaust manufacturers usually include sone ratings in their product descriptions. As you may know, most of the quiet models should have a rating of under 1.0 or 0.5. That’s even quieter than the sound of rustling leaves. And for comparison, a louder appliance, like a dishwasher, might have a rating of 4.0 sones.

Of course, the sone rating isn’t the only thing that determines the noise level a bathroom fan is capable of producing. Its capacity, or rather speed, is another thing you ought to keep in mind.

That particular specification is typically represented by the volume of air the fan can turn within a minute. Most people recommend keeping the capacity of your bathroom fan about equal to the square footage of the room. For example, if the floor takes up 72 square meters, your bathroom fan should have an airflow of 72 cubic feet per minute or more.

Naturally, bigger bathrooms require higher capacity fans. That means that the fans in large bathrooms will naturally be louder than ones that have a more modest capacity. Even so, most people don’t mind the typical low, whirring noise these fans produce. The real problem comes when they start making unusual sounds.

Why Do Bathroom Fans Get Noisy?

Before we talk about how you should go about inspecting and fixing your noisy bathroom fan, let’s take a moment to talk about the potential causes of the sounds you’re hearing. As you can imagine, different kinds of sounds tend to have different and yet distinct causes. So sometimes, putting a name to the noise can be the first step toward diagnosing the underlying issue.

Improper Installation

An improperly installed bathroom exhaust fan can start making all sorts of strange sounds. For one, if the housing component in the ceiling isn’t secure, the whole thing could be shaking any time you turn the fan on.

Alternatively, the different panels and parts that make up the fan may have come out of alignment over time. That tends to happen when the screws and nuts that hold it all together become loose. As a result, parts of the fan — particularly the spinning blades — can start hitting the surrounding materials.

Either way, these issues can cause rattling, vibrating, and even knocking noises when the fan is in motion. However, they’re not the only problem you might come across.

Motor Issues

Depending on the kind of motor your fan is propelled by, the inner parts may require some help to glide along. Certain fan motors might corrode or overheat as a result of a lack of lubrication. If that happens, you might hear squeaking sounds as the parts try to move against each other.

Of course, newer models tend to have a thermal cutoff fuse that doesn’t allow them to overheat. But not all technological additions are as beneficial. For example, if your fan assembly has an integrated humidity sensor allowing it to turn on automatically, it might start powering up on its own. If the sensor is on the fritz, you’ll either have to disconnect it or get an entirely new exhaust.

Grime and Dust

Honestly, when it comes to bathroom fan noise, grime and dust should always be your first suspect. Together, these two can clog the fan grate, blades, motor, and even the air duct behind the fan assembly. That could easily amplify and distort the normal sounds your fan produces.

As a result, you’ll hear whirring, grinding, and even buzzing noises. In fact, you might even hear some of that when the fan is off if the sound is coming from your air duct. But that, at least, has a simple fix — just replace it with a bigger one.

Use a toothbrush to get the dirt off your bathroom fan and stop it from making noise.

How to Address Different Kinds of Bathroom Fan Noise

Usually, most sounds you hear coming from your bathroom exhaust fan should go away after a good scrub of the individual parts. Of course, there are several steps you’ll need to go through before and after you clean those components. So let’s just hop to it!

Get Your Tools

If you want this little project to go off without a hitch, you’ll want to do a bit of prep before you check out the fan itself. For one, you’ll need to get your ladder or even a chair that’s safe to climb onto. Additionally, you’ll need a screwdriver (ideally one with a magnetic tip) or a drill and the appropriate drill bits.

Since bathroom fans are usually on the ceilings, you’ll also want to protect yourself from dust. You can do that by wearing protective goggles and a face mask — or even just some large glasses and a bandana.

Depending on how this all goes, you may also have to order some replacement parts for your bathroom fan. But we’ll cross that bridge when we get to it. For now, you should be all set to start troubleshooting the cause of the noise.

Access the Fan Assembly

Before you get on the ladders, you’ll want to put your protective gear on. That should protect your eyes and lungs as you remove the dust bunnies from your fan’s grille. After vacuuming or brushing the dust off, start carefully prying the grille off the fan housing.

As you pull the panel off, you’ll see two thin spring clips on opposite sides of the panel. To unclasp them, simply squeeze the uppermost parts of the metal wires.

Once that panel is out of the way, you may see a light bulb — depending on the fan model you’ve got. Unscrew it, then detach the light cover by unthreading the wing nut in the middle. Once the panel drops into your hands, you’ll have a wire connecting it to the part above it. It should be easy enough to disconnect — you just have to squeeze the sides of the plastic bit that connects into the panel above.

Next to the light socket, you’ll probably find another cable connected to the electric outlet. That should be the source of power for the fan motor. Unplug it then unscrew the panel. If there’s only one screw on one side of the panel, the part will probably drop down like a hinged door, allowing you to slide it out of its housing.

If there are multiple screws, you’ll have to deal with them all before the panel drops down. Since the fan assembly should be on the other side of that panel, taking it out is a crucial step. If nothing else, it’ll make cleaning and troubleshooting the fan much easier.

Power Up the Fan Assembly

At this point, you should have the whole fan motor assembly laid out on your work surface. It should be attached to the panel you just pulled from the ceiling, with the power cable sticking out on the other side. To find the source of the noise, you’ll probably want to turn the fan on by plugging that connector into an extension cord. Once you do that, the blades should start spinning right away — so make sure your fingers are clear of the fan.

Seeing the exhaust assembly in motion should help you figure out what’s wrong. Are the blades hitting the metal plate the fan is attached to? Are the mobile parts of the motor squeaking? Perhaps you’re noticing a vibration transfer between different components.

Whatever the case may be: don’t worry. Each of these issues has an easy fix. It’s just a matter of locating the issue before you jump into applying the correct solutions.

But of course, before you get to that, you’ll probably notice one pretty obvious problem. If you’ve never taken your fan assembly out of the ceiling, it will be pretty dirty by now! All that dust and grime is probably causing its fair share of noise — so you’ll want to clean it out.

Take the Fan Apart

Before you can determine whether you need to order any replacement parts for your bathroom exhaust, you’ll need to get a clear picture of what you’re working with. With that in mind, it’s time to start disassembling the parts one by one.

If your fan looks something like the one in this video, you’ll start by using pliers to pinch the push nut that’s holding the plastic blades on the threaded shaft that connects them to the fan motor. Taking that bit off will require you to deform it which may result in it breaking. It all depends on how pliable the metal was in the first place. If the assembly is old, you’ll probably have to put in a new push nut when you reassemble everything.

Once the push nut is off, you should be able to remove the blades from the fan motor. After that, you’ll want to flip the metal plate that has the motor on it upside down. That will let you deal with the nuts that are holding the motor in place.

As you work on those and pry the motor off the metal panel, take note of the rubber parts separating these metal surfaces. You should see rubber grommets between the nuts and the metal panel, and a rubber band between the panel and the motor. Those are there to prevent the transfer of vibrations that may cause an unpleasant tapping noise. If the rubber is cracked and worn, you’ll need to replace it when you reassemble everything.

Clean Everything

Once your fan assembly is in pieces, you’ll be able to give all the parts a good scrub. You can use plain old water and soap on any of the plastic parts and even the metal bracket the fan motor was attached to. In fact, you may not even need soap — just a gentle sponge. Just remember to dry everything off when you finish washing it.

Of course, not all parts of the exhaust assembly are that easy to clean. If the fan motor is dirty — as it will undoubtedly be — you’ll want to use a dry toothbrush or a cotton swab to get the dust off. Alternatively, you could get a can of compressed air or improvise one by taping a drinking straw to the end of a vacuum hose you’ve previously connected to the exhaust port of your shop vac.

While you’re doing all this, start noticing if any of the parts you’re handling are visibly damaged. Bent fan blades or even grille bars may produce whirring or knocking sounds if the rotation brings the misshapen part into contact with surrounding surfaces. However, if everything looks okay, it’s time to consider another potential source of the noise you’ve been hearing.

Lubricate the Moving Parts if Necessary

At this point, you should consider applying some WD-40 on the fan — unless the model you have doesn’t require lubrication. Make sure to look into the specs of the motor online before doing anything you won’t be able to change. Still, if the original noise you heard resembled squeaking, it was probably the result of a lack of lubrication.

Of course, you wouldn’t want to sully the components you just cleaned. With that in mind, you might want to focus the WD-40 on the metal shafts that are sticking out of the fan motor. Use paper towels to keep the rest of the assembly clean. Once you’re done lubricating everything, the metal nut fasteners will slide on without an issue.

Reassemble and Run the Fan

Over time, the parts that make up your fan assembly can settle down and end up colliding. If those components touch while the fan is in motion, they’ll cause all sorts of scraping sounds. Therefore, that’s something you should avoid while reassembling the fan.

Do your best to separate the fan components as much as possible. With that in mind, you’ll also want to get your rubber grommets and bands ready before you start the assembly process.

Now, you’ll pretty much work backward to get everything back together. First, you’ll put the fan motor back on the metal bracket that connects to the housing in the ceiling. Remember to put grommets on either side of the metal surface to separate it from the motor and the fasteners on the other side.

One side of the motor will have a long shaft in the middle, which will probably be flat on one side. Take care to align that flat side with the hole in the middle of the fan blade component. Once you match those up, the shaft will slide right through, and you’ll be able to apply the new push nut — if that’s the fastener the manufacturer used.

As you fit the blades over the motor, keep your fingers between them and the metal bracket to create a gap between the two surfaces. Manually spin the fan blades to make sure they’re clearing the other surfaces. You can even plug the fan assembly into the extension cord you used earlier to see if it’s running smoothly.

Replace the Fan Motor or the Blades

If the fan assembly is still making weird sounds, you might have to replace the fan motor. Unfortunately, that may be easier said than done. You see, most manufacturers sell replacement fan assemblies that come with brand new motors and fan blades. So you might just have to replace the whole thing.

Still, it should be easy enough. Just match the parts up with the metal bracket that fits into your ceiling housing and attach them the same way you would have connected the old parts. Remember to put rubber grommets between the metal parts — and screw the fasteners on tightly to prevent knocking sounds.

The Final Check

When that’s all done, you can go on to the final step of the process — putting it all back where you found it. But before you do, you might want to spare a thought for the housing and air duct in the ceiling.

If the fan was never the issue, the noises you’ve been hearing might have been the result of improper installation of the mounting hardware of your fan assembly. If you can move any part of the housing that’s still in the ceiling, you might want to stabilize it before you go on. Depending on the size of the gap on the side of the mounting hardware, you could use silicone caulk, batt insulation, or even expanding foam around the housing.

Lastly, before you put the fan back in, take a quick look at the air duct. The same grime you washed off your fan might have made its way in there too. If you can’t get the clog out manually, you might have to get someone else to check it out.

Once that is settled, you can put the fan assembly back in its housing. Just do everything you did at the beginning of this process but in reverse. You can even take the time to replace the light bulb if you need to. Otherwise, you should be all set to continue using the bathroom normally.

If Nothing Else Works — Get a New Bathroom Exhaust Fan

Even after all this, you might discover that your bathroom exhaust fan is truly beyond repair. In that case, you might decide to get a new, quiet one. If nothing else, attempting to fix your old fan will make you feel like you’ve done all you could before looking for quieter fans.

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