In most situations, mechanical ventilation should be barely audible. If you suddenly hear a humming sound coming from your ventilation unit or fan motor, it's often a sign that something is wrong.
A humming sound can have various causes. Sometimes the problem is easy to solve, but in other cases, a revision or repair of the fan motor may be necessary.
What does a humming sound like?
Customers often describe the sound as:
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a low hum
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a constant buzzing sound
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vibrations in the home
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a sound that is particularly noticeable at night
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a hum that gets stronger at higher ventilation settings
When the sound gradually worsens, it often indicates wear and tear on parts in the fan motor.
Possible cause 1: worn bearings
One of the most common causes of a humming ventilation unit is worn bearings.
Bearings ensure that the motor shaft can rotate smoothly. After years of use, these can wear out. This creates play and increases the noise level.
Characteristics:
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humming sound
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vibrations
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sound gets progressively worse
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fan is still rotating
Possible cause 2: contamination of the fan
Over time, dust, grease, and dirt can accumulate in the ventilation unit.
This can cause the fan to become unbalanced, leading to extra vibrations and noise.
Therefore, regularly check:
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fan blades
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air ducts
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filters
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housing
Possible cause 3: imbalance in the impeller
The fan impeller rotates at high speed.
If it becomes damaged or contaminated, an imbalance can occur.
Consequences:
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humming sound
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vibrations
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increased wear
Possible cause 4: mounting of the ventilation unit
Sometimes the problem is not in the motor itself.
A loose mounting can transmit vibrations to walls, ceilings, and pipes.
Check:
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mounting brackets
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screws
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vibration dampers
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air duct connections
What can you check yourself?
Before considering repair or revision, you can check a few things:
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Clean or replace filters.
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Check the ventilation unit for contamination.
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Check if the unit is securely mounted.
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Check for any loose parts.
If the humming sound persists, it is likely that motor wear is the cause.
When is revision advisable?
Revision is often worthwhile when:
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the ventilation unit is otherwise functioning well
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only the motor shows wear
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replacement is relatively expensive
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you want to extend its lifespan
During a revision, worn parts are replaced, and the motor is checked and tested.
Revise or replace?
That depends on the age and condition of the ventilation unit.
In many cases, revision is a sustainable and cost-effective solution. Especially for high-quality ventilation units from brands such as:
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Itho Daalderop
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Zehnder
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Orcon
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Duco
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Buva
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Vasco
revision can provide many more years of extra lifespan.
Ventilation Service Center is happy to help
Ventilation Service Center specializes in the revision, repair, and replacement of fan motors and ventilation units.
If you are unsure about the cause of a humming sound, please feel free to contact us. Based on the brand, type, and complaint, we can often quickly advise on the most suitable solution.
Frequently asked questions
Is a humming ventilation system dangerous?
Usually not directly, but it can indicate wear that eventually leads to failure.
Can I continue to use the ventilation?
In many cases, yes, but if the noise quickly worsens, investigation is advisable.
Is revision cheaper than replacement?
This is often the case, depending on the type of ventilation unit and the condition of the motor.
How long does a revised fan motor last?
This varies per situation, but revision can significantly extend the lifespan.
Links
DucoBox maintenance and revision
Common ventilation malfunctions and solutions
When to revise a ventilation unit?
Revise or replace a ventilation unit?
How long does a mechanical ventilation unit last?
Zehnder Comfofan making a humming sound?
Stork CML or CMLe making noise?
Buva ventilation making noise?
Vasco ventilation making noise?