Before we dive into this article, here are some links to some of the quietest fans by type that we recommend:

Intermittent fans:
Silent Tornado ST100HT 
Envirovent Silent Design SILDES100HT
Vent Axia Silent Fan VASF100HT

Continuous running fans:
Vent Axia Svara
Silent Tornado ST100DMEVHT
Envirovent Silent Dual

Inline Fans:
Envirovent SILMV250/100T
Vent Axia ACM100T
Tornado Turbo Tube TT100PROT

OK, let’s be honest here - there are a lot of ventilation products out there with names that include adjectives such as SILENT, QUIET, WHISPER etc. But what expectations can we have about the actual running noise of an extractor fan? 

Essentially, manufacturers name anything to make it sound appealing, and we know that this is often a bit tongue in cheek (the Suzuki Swift comes to mind). The two most important factors for extractor fans are “Does it perform well?” and “Is it quiet?”. With performance related to the strength or power of the unit’s extraction rate, we get units with names such as Silent Tornado, MaxiVent, Cyclone, AirVac, Silent Design, Quiet Air, etc, etc. 

Obviously, as a mechanical unit with moving parts, there is bound to be some noise generated and with its sole purpose of moving air, the air movement itself can cause noise through friction against grilles, impellers and ducting.

So, if we are saying that these units will generate noise, how can manufacturers get away with names like Quiet Air and Silent Design etc? Well, It is important to recognise that considering the history of mechanical ventilation products, there is currently a large choice of systems and units that are considerably quieter in function than their historic predecessors. This new generation of extractor fans not only uses a fraction of the power of previous models but incorporates technology such as low friction bearings, brushless motors, cleverly designed impeller blades to reduce friction and drag as well as more aerodynamically designed grilles to minimise friction. 

With these and many other advancements in design, the current crop of modern fans is considerably quieter than their predecessors, and the naming convention is there to tell you this. The irony is that this has happened before, there are many fans still on the market from previous design generations who are not as quiet, but even these have similar names purporting to a near silent running. It is a continuous cycle of improvement which means that the current crop of fans will inevitably be overtaken in the future by newer, quieter units which will also be named Silent, Quiet, Whisper etc. 

But there is another line here that is also worth noting. Occasionally you will have a fan that is claimed to be quiet but is still rather noticeable when installed. This can be due to installation and we will look at these issues in a minute, but it can also be because the unit has the same noise level as its predecessor but is extracting at a higher velocity, meaning it is quieter than it should be relative to its extraction rate!

OK - having established that we can take fan names with a pinch of salt, just how loud are they? 

Every fan listed on our website includes a noise rating measured in decibels (dB). Understanding decibels can be tricky because they increase linearly, while the way we perceive sound follows a logarithmic scale. Essentially, for every 10dB increase, the perceived volume doubles. This means that the difference between 20dB and 30dB is comparable to the contrast between rustling leaves and a whisper, while the jump from 90dB to 100dB is like going from the noise of a hairdryer to the roar of a helicopter!

For most extractor fans, noise levels typically stay below 50dB unless we're dealing with commercial fan units—but this is where things get tricky. The dB ratings provided are based on an average measurement taken from a distance of 3 meters, with the fan operating in a sound-conditioned environment and unattached to any ducting. This controlled setting eliminates variables like natural amplification or additional noise pollution, ensuring a standardized comparison across different models and manufacturers. However, it also means that the listed dB level may not accurately reflect how loud the fan will “sound” once installed in your home. This is because sound can be affected by variables such as the materials in your home, the size of the space the fan is extracting from, where the fan is mounted, etc, etc.

Let’s look at two different fan installation examples, an Inline fan mounted in a loft space and a through-the-wall bathroom or kitchen fan installation:

Inline fan:
Typically, an inline fan is installed in a loft space, with an internal grille positioned in the bathroom ceiling, usually above the shower area. Ducting connects the grille to the intake side of the inline fan, which then directs the extracted air through another duct run to an external vent. This vent can be installed in a gable end wall, soffit, or roof venting kit.

As soon as ducting is attached to the inline fan, the noise level will increase. This happens because the airflow is now being funnelled through a confined space, creating additional noise. As air moves through the ducting, friction against the internal surface generates sound, while sound waves bouncing off the duct walls can further amplify the noise. The overall impact on volume depends on the length of the ducting—longer runs can lead to more noticeable differences in perceived noise levels.
So, how can we minimize this additional noise? First, if possible, opt for solid ducting. Its smooth interior reduces friction, allowing air to pass through more quietly. However, solid ducting isn’t always practical for inline fan installations, as obstacles like beams and joists can make a straight run difficult. While connectors can be used to create bends, it's important to remember that each 90-degree bend adds the equivalent of an extra metre of air resistance. Every fan has a maximum ducting distance it can handle before excessive resistance puts strain on the motor, meaning too many bends can cause performance issues and increased noise.

If flexible ducting is necessary for a more direct run, ensure it is pulled as taut as possible. This maximizes the inner diameter and prevents peaks and troughs on the inner surface, which can disrupt airflow and increase noise. Minimizing slack in flexible ducting will help reduce airflow turbulence, ultimately lowering the perceived noise level of the extraction system.

Choosing the right internal and external grilles is also crucial for reducing noise (we will cover external grilles in the next example). Internal grilles should have fixed apertures with minimal obstruction to airflow. We recommend the following option, available in various sizes and either white or chrome finishes. These grilles provide very little resistance to the air being drawn in by the fan, which helps reduce additional noise caused by airflow turbulence.

There are additional factors we can adjust to help reduce perceived noise, especially with inline fans. Proper airflow is essential—restricting airflow can increase noise levels. Think of how a vacuum cleaner's sound changes when you block the hose with your hand (or the inevitable lost sock from under the bed!). Ensuring a steady flow of air back into the room from the rest of the house not only improves extraction efficiency but also helps minimize extra fan motor noise. Ideally, air should be replaced from within the house rather than through an open window, especially during colder months.

The placement and mounting of the inline fan unit can also impact noise levels. Ideally, positioning the fan equidistant between the internal ceiling grille and the external grille helps minimize noise in the bathroom. Placing the unit too close to the bathroom ceiling grille can increase both airflow noise and the sound of the fan itself.

To reduce vibrations transferring through the building, we suggest mounting the fan on anti-vibration mounts that sit between the fan cradle and the screw points to help dampen noise. It's also important to consider what’s directly below the fan unit. Is it positioned over a bedroom? Is it mounted on a joist that extends over a living space? While some adjustments may require trial and error, a bit of forward planning can prevent unnecessary noise issues down the line.

Through-the-Wall fans:
Fewer variables affect perceived noise with this setup. Ideally, these fans should be installed using solid ducting directly through the wall, connecting to an external grille. This approach provides a cleaner, simpler installation and offers all the benefits we discussed earlier regarding solid ducting versus flexible options.

Once again, ensuring proper airflow into the room is crucial to allow the fan motor to operate efficiently without added pressure. While fan position remains important, with a through-the-wall installation, its effect on perceived noise is minimal.

One factor that can impact perceived noise is the choice of the external vent, which also applies to inline and other ducted installations. Most modern external vents no longer include a fly screen, which used to be a mesh covering for the internal aperture of the external grille to prevent insects from entering the duct. However, the problem with the mesh is that it can trap dust, fluff, and other debris blown through the ducting by the fan. Over time, this build-up creates an obstruction that restricts airflow, reducing the fan’s extraction efficiency. Similar to the effect of blocking the end of a vacuum cleaner mentioned before, restricting the air being vented forces the fan to work harder, leading to increased noise and strain on the motor.

We recommend using an external grille that minimizes resistance and helps reduce backdrafts, as these can increase back pressure, making the fan work harder and adding to the system noise. The No Resist grilles are an excellent choice for wall-mounted extraction points, while the Standard Fixed grille is perfect for soffit extraction. Both options help optimize airflow and reduce unnecessary noise.

In summary, there is no such thing as a completely silent fan, however, they are considerably quieter than they used to be. We do understand that some people can find them an irritant when running but, is it any more irritating than your hoover, hair dryer, washing machine on spin, and countless other household appliances that are usually far louder than an extractor fan? We do appreciate that you don’t get up in the middle of the night to hoover but that when you get up in the middle of the night to use the bathroom, the fan will operate and possibly disturb others sleeping in the house. But there are solutions to this - perhaps install a fan with a humidistat in the bathroom that is not attached to the light switch? This will allow the use of the room without operating the fan unless you shower and raise the humidity in the room, triggering the fan automatically. Or perhaps see if your inline fan has a low speed setting which will still be a higher extraction rate compared to your standard through-the-wall type fans but will drop the operating noise level as a compromise?

Most importantly, the benefit of a working extractor fan should far outweigh the irritation of any noise, by maintaining a healthy indoor air quality, you improve the health of the occupants and the building structure itself and keep hazards like damp and black mould at bay.