How to Make Inline Fan Quieter:7+ Effective Techniques

wondering how to make your inline fan quieter?. Well, you are not alone. I have seen many gardeners and homeowners ask this question a lot of times.

Today we will look into some of the effective ways to make your inline fan quieter.

Inline fans come in many different configurations, sizes, and capabilities to meet a wide variety of ventilation needs. They are available as single-port versions or versatile multiports versions.

How to Make Inline Fan Quieter

Inline fans can be used for a variety of applications such as ventilation of wet spaces such as bathrooms, and kitchens, remove fans for kitchen range hoods, duct boosters for ventilation systems and clothes, for grow rooms ventilation, and supply or exhaust fans for continuous whole-house ventilation or even for radon mitigation systems.

However, with all the uses and help that inline fans can offer, the one downside that most users are battling with is the noise that these fans make when running.

But, how loud is too loud as long as inline fans are concerned?. Well, the answer is based on several factors such as location, type of fan, length of the duct, and many more.

Usually, when the noise level goes above 75 dB, it is considered loud and something needs to be done to reduce the noise level.

The noise level can be determined using a dB meter by placing it in front of the airflow once the inline fan is on.

Also Read:

Best quiet desk fans

Ways to make an industrial fan quieter

Causes of Fan Noise

The causes of noise emanating from ventilation fans are a function of many variables and causes. Here are the possible causes of fan noise.


The higher the fan speed, the louder it becomes. For instance, if a fan speed is reduced by 20%, the noise level (dB) will also be reduced by 5 dB.

Vortex Shedding

This kind of noise is generated by the air separation from the blade surface and trailing edge. To control this kind of noise, you will need a good blade profile design, proper pitch angle, and notched or serrated trailing blade edges.

Fan Load

When fans are operated at their maximum efficiency, they tend to make more noise. You load them with a lot of work and as a result, their components make more noise. This type of noise is similar to the one that comes as a result of high speed.

Structure Vibration

This can be caused by the components and mechanism within the fan, such as residual unbalance, bearings, rotor to stator eccentricity, and motor mounting, motor mounting noise can be difficult to define.

Fan Noise Reduction Techniques

1). Isolate the Fan with a Cardboard

Isolating the fan with a wooden box is one of the simplest yet effective ways of reducing inline fan noise. The enclosure is lined with a noise-absorbing material. This will greatly lower the noise levels as both materials are sound absorbers.

If you are a bit handy, you can create your own DIY fan silencer fan with these materials. However, if you are not willing to make one yourself, you can invest in an already made inline fan silencer box that is available online.

But you’ve to avoid keeping the box in direct contact with the fan, rather suspend it from the ceiling or walls this will prevent vibrations and will worsen the noise.

Noise absorbing box that is suspended from the roof will absorb a decent amount of noise and also prevent vibrations from going through the walls.

2). Use Inline Fan Insulating Ducts

Some of the noise you will hear from your inline fan will pass through the ducting. And the best way to deal with this kind of noise is to use insulation.

You get to deal with the noise before it escapes from the ducting.

You can purchase online at Amazon if you don’t already have some. Choose ducts with the same diameter as your inline fan.

Another benefit of using insulating ducting is it will run the fan cooler. This will shield both the intake and exhaust fan from hot temperatures especially inside a grow room.

3). Invest in a Fan Speed Controller

Speed controllers are great to have especially if you are trying to get rid of shattering noises when the fans run in full swing.

The speed controller allows you to have the ability to dim down the fan and have control over the noise as well.

If you intend to get a speed controller, then you need to watch out for these. First, if you slow down your fan, you may not be able to meet the ventilation requirement of the grow system. This will require you to install additional inline fans which will cost you more money.

Secondly, if you purchase the wrong grow roo fan speed controller that is not compatible with your fan, you use your controller for a while but if it’s not operating at the right voltage, the fan may die prematurely.

4). Use Neoprene Duct Clamps to Join the Fan and Filter/ Silencer

Using a neoprene duct clamp as a joint media in between the fan and filter/silencer is a great way to suppress the vibration made by the inline fan and the adjacent fan filter or duct silencer.

Vibrations amplify much more at these kinds of joints. To overcome this, that is why you need to neoprene clamp as a joint media between the fan and the filters.

If done properly, that will definitely lower the grow room fan noise by a few decibels.

5). Use Muffler

A vent muffler has better noise insulation than a silencer duct. I already made mention of the silencing duct above. But if you want to reduce the noise further, an inline fan duct muffler is more effective.

A duct muffler can reduce the noise up to 25 dB. If you add aluminum ducting with it, the reduction is even more, especially in the bending areas of the duct.

You can easily purchase an already made inline fan muffler online or make one yourself.

6). Soundproof the Room

If after these techniques, you still find it hard to deal with the inline fan noise, then you can soundproof the room from the source of the noise.

Soundproofing a room involves the doors, windows, floor, and ceiling. You can look at the bigger culprits of the noise, like the windows by covering them with soundproof curtains or blinds.

To take care of the floor vibrations, you can use a soundproof carpet or vinyl mat on the floor. There are many ways to soundproof a room without employing invasive methods.  Check out How to Soundproof a Room DIY Ways.

7). Buy A Quiet Inline Fan

The best way to deal with noises from your inline fan is by buying a quiet fan. You get to deal with the noise even before it causes any disturbances.

I recently did an article on the best quiet inline fans that will lower the noise of your ventilation efforts.

Final Thoughts on How to Make an Inline Fan Quieter

Inline fans can be incredibly useful in many applications but they can also make a lot of noise. If you value your peace of mind, then working to reduce the noise levels is important.

The above techniques will help you reduce the noise levels drastically and if you don’t want to go through the hassle of working to reduce your existing inline fan noise, then you can invest in a quiet inline fan.

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