Man fixes a noisy bathroom fan

How To Fix A Noisy Bathroom Fan

If you’re dealing with a case of a noisy bathroom exhaust fan, you’re in the right place. 

There are several reasons why an appliance of this type may become louder than it’s supposed to be, but it’s usually one of the few most common culprits. I’ll go over each one of them in more detail. 

In this guide, you’ll read about: 

  • Checking the vent duct; 
  • Oiling the wick bearings;
  • Cleaning the grille cover;

…and more. Let’s get started!  


The Introduction 

Among new homeowners, a bathroom exhaust fan producing far more noise than it should is undoubtedly among the most common complaints. 

This is particularly true for those who own “builder-grade” bath fans, i.e. cheap and not-so-good quality models. Not only are such units much louder than their premium-quality counterparts, but they also tend to get even noisier as they age. 

When an appliance of this type gets older, several issues may appear and make it frustratingly loud. The duct can start to impede the model’s airflow, or its grille may become clogged with dust. Furthermore, the blades of the fan can become misaligned and its engine can lose lubrication. 

All of these problems can turn a bathroom exhaust fan into one annoyingly loud machine. However, all of them can also be fixed – here’s how: 

Step #1 – Dirty Grille Cover 

Person removing a bathroom fan cover

As someone who knows a thing or two about bathroom exhaust fans, I can’t tell you how many times in my life I have seen dirty or clogged grille covers. 

What most people don’t realize is that a bathroom exhaust with a dirty grille cover can very easily become a potential fire hazard. In fact, a fan that’s dirty in any way is much more prone to overheating than the clean, well-maintained appliances of this type. 

In most cases, the grille cover will be the only actually “visible” part of a bathroom exhaust fan. Usually sporting a beige or plain white color, these covers can quickly and easily become clogged with all sorts of debris and dirt. 

Unfortunately, a vast majority of homeowners simply don’t bother with cleaning bath fan grille covers, despite the fact that cleaning this part is as easy as it gets and can be done in a couple of minutes. And a grimy grille cover can make a bathroom exhaust fan very noisy. 

With the greasy cover stopping the appliance from sucking in a sufficient amount of air, the fan will start making weird noises. Take care of this issue by detaching the cover, rinsing it thoroughly, and then re-attaching it once it’s completely dry. 

If you’d like to clean the entire appliance – not just the grille cover – make sure to check out my article on cleaning bathroom exhaust fans

Step #2 – Dried-Out Engine Bearings

Bathroom with a noisy fan

Older models of bathroom exhaust fans typically have oil wick bearings. 

Those who own such bath fans are supposed to periodically lubricate these oil wick bearings with some light engine oil. However, just like in the case of grille cover cleaning, most people simply don’t do this. 

The condition of these bearings decides whether a fan’s motor will run smoothly or not. If you fail to maintain the bearings with the aforementioned light engine oil, they will go dry and give the motor some serious trouble. Obviously, a rough-running fan motor will be far noisier than a smooth-running one. 

A few months ago, I oiled one of those popular Broan-NuTone bathroom exhaust fans and it made a massive difference in terms of noise. What is more, oiling also made the fan run far more smoothly and efficiently. 

In order to be able to oil the wick bearings, one has to completely remove the motor from the exhaust fan and then uninstall the bearing brackets. You can use almost any kind of light engine oil – just put a couple of drops of it on each part that needs oiling. 

You can read more about all of this in my guide on oiling bathroom exhaust fans

Step #3 – Fan Blade Misalignment 

Bathroom fan blades

While removing the engine of the exhaust fan in order to oil it, it’s a good idea to also check the fan’s blades and ensure that they’re spinning correctly. 

In case one of the blades is acting kind of “wobbly” while it’s spinning or if it’s hitting something during operation, that is probably why your bathroom exhaust fan is making so much noise while running. 

Simply spin the blades with your hand and determine whether there’s anything weird about the way in which they’re spinning – if it’s not balanced and smooth, you’ll probably have to do some fixing or replacing.  See our post on how to fix a bathroom fan that stopped working as well.

Step #4 – Too Many Duct Bends 

Having too many duct bends is yet another issue that can cause a bathroom exhaust fan to produce more noise than it’s supposed to. 

Each duct bend contributes to the overall amount of air resistance. And if there’s too much air resistance, there will also be too much noise. 

In an ideal kind of situation, a fan duct will have no more than 3 bends and there won’t be any 90-degree turns. For maximum airflow (and, therefore, reduced amount of noise), the bends need to be gradual and smooth. 

One particularly effective way of reducing the noise produced by an exhaust fan is choosing metal instead of flexible ducting. The ridges inside flexible ducts are quite prone to creating air resistance, which, as I mentioned above, significantly contributes to the overall amount of noise produced by an exhaust fan. 

Step #5 – Clogged Duct

Ducts on an exterior wall

The birds really like making nests inside dryer vent ducts and bathroom vent ducts – there’s no doubt about that. 

As you can already guess, a bird’s nest can bring the airflow to a complete halt. This won’t only increase the amount of noise produced by the fan, but also significantly impact its performance in a negative way. 

The easiest way of checking whether there’s adequate airflow in the duct is by simply turning on the appliance and checking outside for airflow. The cover of the vent should have a so-called flapper, which opens up every time the exhaust fan is in operation. 

Obviously, if the flapper is not open, there’s no sufficient airflow in the duct, i.e. the duct is most likely clogged. 

Step #6 – The Duct is Too Small 

Unlike the older models, which used 3” ducts, most modern bathroom exhaust fans require the use of larger ducting. 

If you’ve just bought a brand new appliance of this type, there’s a pretty good chance you’re going to need a 4-6”-wide duct for it to work properly. 

Using an undersized duct is guaranteed to negatively impact the performance of your new bathroom exhaust fan and also make it noisier than it should be.

Check out this guide if you are wondering how much electricity a bathroom fan uses.

The Takeaway 

As you can see, there are quite a few issues that can make a bathroom exhaust fan rackety and loud, and most of them can be fixed quite quickly and easily. 

If the problem persists no matter what you do, i.e. if cleaning and oiling do not give any results, I would recommend just buying a new model, preferably one of the best-rated quiet bathroom exhaust fans

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