Whether it’s the ceiling fan in your bedroom or the bathroom exhaust, fans, in general, produce a slight humming sound – and that’s pretty normal. But as the minimal hum turns into a loud rattling and knocking sound, it becomes extremely annoying to shower in, let alone take those hour-long weekend baths.
If you’re missing the old serenity of your bathroom because of the noisy exhaust fan, it’s high time to carry out some repair work. From identifying the causes of a loud exhaust to suggesting easy repair techniques to fix a noisy bathroom fan, we have gathered everything you need to reclaim the peace.
Cleaning and lubricating the fan blades, hub shaft, and motor bearings are the first steps toward fixing a noisy bathroom fan. If your bathroom exhaust fan is making a rattling noise, realign the fan blades to reduce the wobbling and embed the internal casing with rubber stripes to dampen the vibrations. In the case of constrictive ventilation ductwork, you can also implant a duct adapter to maximize the airflow.
Why Are Bathroom Exhaust Fans So Noisy?
Since exhaust fans are constantly propelling warm and steamy air out of the bathroom, many believe the humming sound to be a consequence of that – and rightly so. With the constant airflow and rotating blower wheel in the exhaust, some noise from the ventilation exhaust is inevitable.
Under optimal conditions, a bathroom ventilation fan should emit 1.0 sones or less sound. Many advanced fans are usually quieter unless they’re faulty or have lived past their warranty period.
If the sound intensity increases from the set threshold, a possible malfunction may be the underlying reason. There are plenty of ways to soak up the vibrations and loud rumbling, but let’s first identify the main culprits behind noisy bathroom exhaust fans.
No matter what machine they are installed to, motors have a lot going on in terms of mechanics. The constant motion of these moving parts emits vibrations, producing a humming and grinding noise as a by-product.
Since the exhaust fans are mounted to the bathroom’s ceiling, the vibrations dissipate into the ceiling as part of structure-borne noise. Such vibrations are often a sign of imbalanced fan placement, potentially damaging the fan blades or the motor itself, if not dealt with.
Except for the older models, most modern bathroom fans rely on the blower mechanism. While the basic concept is the same – propelling warm and moist air outside through the same channels, blowers steer the outflowing air to a specific area. The airflow in either direction creates a delta pressure or vortices that generate a loud squealing noise.
Like typical ventilation ducts, the exhaust ducts also support the free movement of air in and out of interior space. Since the ducts are instated into the fan’s housing, the humming and squealing sounds from the fan could easily wander through to the other side.
Not to mention, sound waves that bounce off inside the duct surface potentially generate loud echoes that contribute to the exhaust fan noise.
Common Noises in a Faulty Bathroom Exhaust Fan
In most cases, the sounds made by bathroom exhaust fans are perfectly normal – but they are just too loud to relax. Whether they are a by-product of structure-borne vibrations or the loud reverberations produced afterward, here are a few common noises you are likely to hear from a faulty bathroom fan:
- Grinding – When the fan blades and shafts accumulate dust and lint over time, it sounds like a grinding noise when turned on.
- Rattling – Often a sign of forceful vibrations caused by a wobbly casing, loose fan mount screws, or misaligned fan blades. Rattling gets louder as you operate the fan at high speeds.
- Squealing – Misaligned or loose fan casing often leads to squealing noise – a sign of high friction between the moving components.
- Banging – Besides the shaft and motor hub, the fan blades also rub against the outer grille resulting in loud squeaking sounds.
- Other high-pitched sounds – Bathroom exhaust fans don’t always make the same sounds. If you have an older exhaust fan, you might also hear loud, high-pitched noises signaling a worn-out motor.
You don’t have to be a technician to silence a noisy bathroom fan, given it has a minor issue. But if you are dealing with worn-out motor bearings or winding, you might require special expertise from an HVAC professional.
Repairing a Noisy Bathroom Fan — The 5-Step Formula
When designing your dream bathroom, setting the right mood can be challenging, especially if the bathroom fan is making a rattling noise. If you’re struggling to reduce the bathroom exhaust fan noise level, we have set up a five-step formula to help you with the unbearable loudness.
Clean and Lubricate the Fan Motor
Any negligence in cleaning or maintaining the exhaust fan may cause dust to build up on the fan hub and motor shaft. When combined with lubricant, the accumulated dust forms a thick grime on the motor bearings that wear off with time.
Lack of lubrication results in loud squeaking and rumbling noises from the motor hub when the fan blades rotate. Not to mention the high risk of rust formation. If you are experiencing the same, use WD-40 lubricant spray on the most noise-prone areas. Repeat the following procedure to lubricate the exhaust fan effectively:
- Switch off the fan to unscrew and remove the fan grill cage.
- Use a damp microfiber cloth to clean the dusty fan blades or the blower to prevent the formation of mold and mildew. Consider using an old toothbrush for an all-out cleaning.
- Now apply the lubricant spray on all moving components and spots showing signs of rust.
- Reattach the grill casing and turn on the fan. See if you notice any change in the noise.
Realign the Fan Blades and Hub Shaft
Running your bathroom exhaust fan while it’s cloaked up with dust and debris can distort the alignment of fan blades. The weight swaying towards one side of the fan frequently clangs with the fan grilles, resulting in an annoying clinking noise.
Regardless of the distressing grinding noise, fixing or realigning the fan blades and hub shaft is fairly easy. Simply disassemble the fan blade from the exhaust and set it on a straight desk to assess the degree of misalignment. Since most bathroom exhausts use plastic fans, all you need is to push the edges of the fan propeller to set them into place.
Infuse Rubber as Insulation
Despite the lubricated hub shaft and aligned fan blades, sometimes it’s the extreme vibrations from the motor that disturb the bathroom environment. The vibrations are noticeable by their buzzing or ringing sounds.
If lubricating the motor hubs don’t seem to dampen the vibrations, it’s better to take a more physical approach. Sticking Sorbothane rubber stripes inside the vent around the motor will help soak up those excessive vibrations. Even though it’s thinner than most anti-vibration pads, the Sorbothane rubber offers impressive shock absorption.
Secure the Mounting Screws
Be it the outer casing that encloses the exhaust fan or the internal clips and brackets that secure shaft hubs and motor, loose screws are cancerous. Besides displacing the motor assembly, unfastened screws cause intense vibrations, which lead to clicking and jumbling sounds. Examine all screws and nuts on your exhaust fan, and tighten the ones you find loose and wobbly on the spot.
Set up a Duct Adapter for Constrictive Ventilation
When it comes to ventilation ductwork, bathrooms don’t receive the same attention as other sections in your home. Regular whooshing or buzzing sounds from the exhaust fan often indicate constrictive ventilation.
To dilate the duct pipes in your bathroom, install straight duct adapters. The added airflow space allows exhaust fans to suck out the air more effectively after your showering session. Make sure you use duct tape to seal the adapter on the ventilation.
Upgrading to a Quieter Bathroom Exhaust Fan
While fixing a bathroom exhaust fan to reduce the noise isn’t rocket science, the repairing techniques might not work if the fan has already exceeded its recommended lifespan. In such cases, it only makes sense to upgrade to a quieter model. But is your bathroom exhaust fan nearing its end? Here’s how to know:
- Even though it mainly depends on maintenance and upkeep, the average lifespan of a bathroom fan is ten years. Some might stay operational after ten years, but they will most likely die out when the next inconvenience hits.
- When repairing the noisy bathroom fan, you often have to replace the entire motor unit to get it running again. Considering their exorbitant costs, purchasing a newer bathroom exhaust seems economical.
- Modern bathroom exhaust fans are more energy efficient, keep your energy bills to a minimum and produce less noise than their traditional counterparts.
People Also Asked
Before we end, here are the answers to a few common questions:
What is the ideal noise level for bathroom exhaust fans?
According to the general guideline, noise emissions from a bathroom exhaust fan shouldn’t exceed 1.0 sones. You should also ensure that the bathroom fan operates at 400 CFM or low.
Are noisy bathroom fans dangerous?
Although it’s not fatally injurious, bathroom fans with extreme noise could mean trouble for the motor. It’s clanking against the grille cage or vibrating forcefully against the shaft hub may be the reason for the noise. Either way, you must get it repaired immediately.