Noisy Bathroom Fan | Is It Dangerous?

A noisy bathroom fan is a sign that you need to perform some repair or maintenance to the exhaust system. Mostly, these sounds are the start of bigger problems or inconveniences for you, but they aren’t dangerous.

Many noises are harmless, even though they need to be addressed. However, there are a select few sounds that should prompt you to more urgent action. These sounds are related to the unit’s electrical components, which must be kept in good working order.

A high-pitched whining indicates insufficient lubrication, an electrical humming comes from a wiring problem, and grinding points to significant dirt buildup. If the source of any of these sounds is left unaddressed, the fan may start a fire.

Contents show table of contents

Few Bathroom Fan Noises Indicate Danger

Bathroom fans are not particularly dangerous appliances. They are not involved in transporting flammable substances, conducting electricity, or providing heat.

They can be noisy, and often this noise indicates something is wrong, just not necessarily dangerously wrong.

However, bathroom fans are electrical devices, and, as such, there is the potential risk of an electrical fire starting. The issues that could lead to this may present with noisy indicators, so it’s a good idea to investigate. There are a few reasons why a fan is making a noise, but only a few of them are problematic.

Dangerous Bathroom Fan Noises

High-Pitched Whining

A high-pitched whining is a sign that something is going wrong with the motor’s function. The motor is an electrically powered part of the fan, so this is a noise that you should take care of as soon as possible.

The whining is likely happening because the fan is improperly lubricated. Lubricating oil is essential to the bearings of the fan’s motor, as this fluid is what allows the blades to rotate smoothly and quietly.

The whining comes from the contact of the bearings as the motor turns as they move without enough slip. The whining is a sign that your motor will eventually seize because the bearings will eventually stop moving entirely.

If the motor seizes, it can overheat because the current the fan draws (which will increase) is not converted to kinetic energy and instead turns into heat. If your bathroom fan overheats, this can result in a fire, and the current the fan ends up drawing might not be enough to trip the appliance’s breaker.

Addressing the Issue

Newer fan models are designed to be permanently lubricated, eliminating the need to refill the oil supplies in the motor. This might be why you were unaware that lubrication could be an issue.

Here are the steps you need to follow to reach the motor to refill the oil:

Shut off power to the fan at the main breaker (ensure no one will turn it on while you are working).
Confirm the power to the fan is off by trying to turn it on. Then, turn the switch off again so the fan won’t start if power is restored.
Pull the fan cover until you meet resistance, then squeeze the clips on the sides to release it completely.
Disconnect the wires from the fan assembly (you can label them or take a picture of which goes where).
Then unclip the fan assembly.
Deconstruct the assembly (take a picture to remind you of where everything goes) to remove the motor and blades.
Clean everything off before applying the oil to the components and the bearings.

Lay all the parts out on a cloth or paper and ensure that you apply oil to all sides before putting the fan back together and restoring power.

Take the motor shaft out, and you can now lubricate the parts. You will need to oil the shaft and add oil to the oil wick bearing, which has a hole on the front for oil to be poured into.

Illustration of rear and front of oil wick bearing

When you put the motor back together, knock the shaft from all direction and check it spins both ways easily.

Electrical Humming

An electrical humming sound can occur if there is loose wiring in the fan housing. This can happen when dirt and debris knock a wire or if the wire is not installed correctly. The noise that results from loose wires is actually pretty loud, making it hard to miss.

Considering the fact that loose wires are a fire hazard as the electricity is not being contained and channeled into the appliance, it is vital to resolve it quickly. When this happens, the energy escapes as heat instead of staying in the wires.

Alternatively, the current won’t be directed into the fan’s circuit appropriately, which can potentially electrify the fan, making it dangerous to have in a wet bathroom and to handle. Any exposed wiring is open to moisture, which is bad news.

Addressing the Issue

You don’t need to take the fan fully apart to get to the wiring; you just need to get under the cover.

However, I recommend you don’t address the issue yourself; instead, call an electrician as soon as possible if you suspect you have some loose or broken wires.

There are two main reasons for this recommendation. Firstly, if you don’t know what you are doing, then it is very dangerous to mess with electricity. Secondly, it is illegal in many states to perform your own electrical work or repairs.

An electrician has the knowledge, experience, and professional certification to fix wiring problems, preventing the fan from overheating and posing a fire risk. The electrician can also ensure the wiring problem is local to the fan assembly and can sign off on the work as safe and appropriate.

I would avoid using the bathroom fan until it can be checked and repaired. This helps prevent an electrical fire from starting.

Electrician removing and repairing the bathroom fan

If you need to control the steam in the meantime, you should read my article on moisture control in bathrooms without exhaust fans.

The risk of electrocution increases since you don’t know what the damaged wires are touching. So, you can even turn off the breaker for the fan to prevent power from reaching the unit.

Grinding

A grinding sound in the bathroom fan indicates a buildup of dirt in the fan motor and housing. This will prevent parts, like the blades, from moving freely.

A bit of dirt doesn’t sound particularly insidious, but if the parts of the fan cannot move properly, this can strain the motor.

The motor must work much harder than usual to make the fan move since the appliance’s moving components are designed to do so easily. The extra strain on the fan motor increases how much power it draws and can result in an overheating problem.

Addressing the Issue

To address the issue, you need to clean the fan. This requires dismantling the fan and the fan assembly to get all the separate parts out:

Shut off power to the fan at the main breaker and ensure it won’t be turned on by accident.
Confirm the power to the fan is off by trying to turn on the fan, then returning the switch to the “off” position.
Pull the fan cover until you meet resistance, then unhook the cover completely by pressing the metal clips on the side.
Disconnect the wires from the fan assembly (make sure you note where they go).
Remove the fan assembly.
Take the assembly apart (ensure you know how to reconstruct it) to remove the motor and blades.
Now you can clean everything to get rid of any dirt.

To clean everything, you can use a vacuum and toothbrush; just be careful not to break any components.

Man wearing gloves while cleaning the bathroom fan cover using a toothbrush

The blades should be washed with some warm soapy water.

You can also check the shaft where the fan assembly comes from to make sure you are doing a thorough job while you are at it.

You will have to reapply oil to the parts to make sure that the cleaning didn’t remove any necessary lubrication.

Sounds That Are Not Dangerous

Some noises aren’t immediately dangerous but still indicate problems that can impact your fan’s effectiveness or build to bigger issues within the exhaust fan unit.

Dripping

Fans can make a dripping sound when condensation forms in the ducting or if rain or snow is getting in. This points to the fan’s power, ducting, insulation, or flashing/vent cover.

Noise When Off

Some problems present as noise when the bathroom fan is off:

It might be an issue with the backdraft damper or vent cover. This can cause dripping, rattling, banging/clunking, or you might hear the scurrying of insects.

It might also be that your fan isn’t off if you constantly hear the fan whirring. You might just have a dual-action fan, but this can also result from wiring problems or a broken humidity sensor.

If you live in an apartment building and hear a noise when your fan is off, it might be your neighbor’s fan in a shared ventilation shaft.

Fan Assembly

If you hear a rattling or buzzing noise while the fan is on, it is probably the result of loose screws and parts in the fan assembly.

Squeaking indicates that you need to lubricate the fan but isn’t pointing directly to the bearings.

A knocking or clunking sound when the fan is on indicates a misalignment in the fan.

Buzzing or humming indicates dusty or blocked blades (causes vibration) and the start of a more significant grinding signal.

Buzzing Timer Switch

If you have ever been buzzed through a door or security gate, you have an idea of how to recognize this distinctive timer sound. It comes from a wiring issue or unit defect.