Ducting silencers, do i need one?

Ventilation silencer

Ducting silencers, do i need one?

What are they?

On a hot summers’ day, there is nothing nicer than having a cool breeze flowing through your house. Either through an air con unit or through standard ventilation ducts. Everyone knows how important it is to have good ventilation. You don’t want to have stale air and mould flying all over the place.
The problem with this? The noise! Hearing the fan noise through the duct-work when you have counted your five hundredth sheep and are panicking about how many minutes sleep you can get before you get up for work would stress anyone.
woman lying awake on bed
Another sleepless night
If you have paid for an air conditioning unit for your family to enjoy during the long hot summer months. Now you find that the noise the air conditioning unit creates is more of a barrier to sleep than the heat. It is difficult to find a “silent” air con unit, but some are a little less noisy.

Step in the ventilation silencer!

A silencer also has the far less exciting (but far more accurate) name of an “Attenuator”. This means that it reduces something, and that “something” in this case, is sound.
It’s not true that a “silencer” cancels all noise from these appliances. Sound is reduced by the installation of one of these units.
The reduction of noise is enough to be something to think about when looking at your home ventilation systems. Many people forget the noise produced by the fans pushing the air through. This applies to the sound of air flow through the vents in your home, or your neighbors’ arguments. So it’s a great way to reduce the noise between rooms too.
Large fan
It can feel like you have one of these in your home without a silencer

So, there we go, a vent silencer reduces the noise travelling through your ventilation. seems simple enough doesn’t it? Most people would not think of adding attentuators in duct-work, but it’s an easy solution to a problem.

How a silencer works

Silencers have different ways of dampening sound, and our systems use “passive” attenuation. They absorb the sound that passes through the silencer without needing any more current, making it a cheaper solution.
Sound moves in waves, when the sound wave passes through the sound reducing material, the waves are disrupted. This creates more resistance in their path and so lessens what bounces back to our ears.
Our models use the before mentioned mineral wool. You can choose how thick you need the insulation to be depending on what you are trying to reduce. If you’re looking to dampen the sound of air moving through the vents, you only need 50mm of insulation. If you have a noisy cooker hood or extractor fan the 100mm insulation would be best.


If you are baffled by baffles, then let me explain a little more about them. I am certain you have seen this product before. If you imagine a recording studio, you might have noticed that the walls have got an odd shape to them. They have squares of triangular material, similar in shape to an egg box.
Bafflers in a soundproof recording studio
No more hot and sweaty recording artists
These are used in areas like concert halls or anywhere where you hear a large amount of “echo”. This is the sound bouncing off hard surfaces such as walls. The baffles will absorb the sound waves instead of letting them bounce off the walls.
DIY recording studios have egg boxes covering their walls. This is the same idea but on a smaller scale than a professional set up, and is not as efficient.
In the vent systems for most recording booths, they would have a silencer in the units above. You can’t have someone sweating in those booths whilst they are recording. They also cannot have sound from the ac unit being picked up on the recording, so a silencer stops this. This is something to think about if you are organizing your own sound booth.

So why don’t we use baffles in all our duct silencers?

Baffles are very efficient and great at dispersing sound waves, so why don’t we put them in all our vent silencers?
The issue we would have with doing that is that they are efficient at creating sound resistance. They also cause a great deal of air resistance (not great news when you are trying to ventilate something).
In a ventilation duct, too much resistance will require a powerful fan to get sufficient air flow. Mineral wool instead of a baffle creates enough resistance to the sound, without reducing the quantity of airflow.
You can opt for the baffle to be included in your silencer if you would prefer. A professional can tell you your options regarding fans. Understanding the power and size needed can be difficult when putting baffles to a vent system.

What are our solutions?

Here at I-sells.co.uk, we understand everyone has different needs. If you are looking for help on putting in vents or how to DIY soundproof a room we can help.
We have silencers in a range of sizes and diameters to suit every scenario. Please give us a call on 020 8463 9696 to speak to our ventilation experts.
You can see our full range of silencers HERE.

Ventilation silencer

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