This week I have been asked again about how to stop noise through vents. I have previously detailed an extensive guide on how to soundproof air vents above a door, but today wanted to go into a little bit more detail on my approach.

The guide to stopping noise coming through an air vent is both easy to follow, and relatively quick. I have also suggested some product recommendations so you know exactly what you need – the products are very cheap.

The steps below contain both quick methods, and more advanced procedures. If you have any other methods then I would love to hear them, but these are real-world guides that I have implemented in my soundproofed home office.

Why Noise Travels Through Vents?

By design, houses are acoustic nightmares. You will have multiple reflective surfaces such as walls and corridors, plus not many paths by which sound transmission can be broken.

Air vents will carry conversation and noise around a house which can be disruptive, in particular if you want a room to be soundproofed for multiple reasons.

You have two options available to you, should you wish to stop noise coming through a vent. They are:

  1. To block the air vents completely (not recommended)
  2. Install a self-made sound maze construction inside of them

In addition to those two options, you can also improve how the rooms in question treat an “deaden” sound, but I will come onto those aspects towards the end of this soundproofing guide.

How to Stop Noise Coming Through Vents

Below are my steps and solutions. Please note the one that I advise is solution number 3.

The first two will work, but have far too many drawbacks and negatives to really be seriously considered – not just from a practical angle, but also from safety perspective.

Solution 1: Towels (Not Recommended)

You could block up air vents with towels to absorb and stop noise travelling.

But, my opinion on this is that it’s potentially dangerous and this is why.

Should your boiler leak and there isn’t enough adequate airing in the room, it could be very, very dangerous.

Houses that have open solid fuel or gas appliances will require ventilation. When a fire burns it uses up oxygen in the room, far faster than us humans can. Having effective ventilation (your air vents) will mean you will be far safer in the event of any carbon monoxide leaks.

So, with that in mind, I would not recommend that you block up air vents to prevent noise and sound coming through.

Admittedly, it’s probably a very low risk, but I am not one to take risks with my own family, and believe you probably feel the same way.

Only block the air vents up if you have enough alternative ventilation in the room such as windows and doors out into properly ventilated corridors.

Should you end up blocking your vents, then make sure you invest in a carbon monoxide detector. In fact, you should have one of these anyway in your home as they can be a potential life-saver.

The carbon monoxide detector that I use in my living room and around the house (we have 3 detectors) is the Kidde KN-COPP-3 Nighthawk plug-in. It has a battery back-up in case of power failure, or if you want to carry it to another room.

Make sure you purchase carbon monoxide detectors to keep your family safe, regardless of whether or not you are blocking sound from coming into an air vent.

Solution 2: Expanding Foam (Not Recommended)

You can permanently block air vents using expanding foam products. Again, it could have implications for safety, plus also means you could end up with a very warm room in hot summer months.

If you do decide to go down this route, another aspect to consider is whether or not you will be selling the house in the near future. Having air vents blocked up with expanding foam isn’t really going to be a great sales point.

The brand of expanding foam I use for my soundproofing projects is Great Stuff. It’s the best on the market and you can buy it cheaply on Amazon.

Similarly, as with the first solution, make sure that you use carbon monoxide detectors in your home if you are going to be blocking any air ventilation from noise.

Solution 3: Purchase Acoustic Air Vents (Expensive)

Some companies actually manufacture acoustic air vents, but they can be expensive. See how they compare on Amazon. They are advertised as a soundproofed solution which will let ventilation into rooms.

I’ve never purchased these products, so cannot vouch for their effectiveness. Having said that, the science behind them is sound, and reviews are very good.

Which leads me on nicely to my own DIY solution.

Solution 4: Build Your Own Sound Maze

This is my own home-made version of an acoustic air vent, and a project that I have successfully completed in my own home office. It might look complicated, but honestly, it’s not and is simple enough for an intermediate DIY person.

As discussed, we should not close-off, block, or restrict air flow into a room.

So how do we reduce and stop noise coming through the air vent then?

A sound maze should do the trick and here’s what they look like.

How to Soundproof an Air Vent with a Sound Maze

This is how your sound maze will work in your above-door air vent.

You cut small pieces of wood as panels which you then cover with acoustic foam for additional soundproofing. Once those panels are built you glue them into the air vent as shown above.

What this does is still let air flow through the vents, but makes the sound zig-zag through the structure – this lessens the volume each time, as the noise is absorbed into the panels in the maze.

What You Will Need

If you want to build your own sound maze in your air vent then here’s what you are going to need. I assume you will already have the tools, and can get hold of wood, so have just linked you up to the best deal on acoustic foam that I can find.

It took me approximately 2 hours to complete one sound maze build and installation.

It works very well.

It doesn’t stop 100% of noise, but has significantly reduced the noise and conversations coming through the vents in my home.

I would love to hear how you get on with this project, and hope that it helps!

Additional Tips on Stopping Noise Coming Through Vents

The sound maze solution is the first thing that I would do. To further improve matters there are some acoustic hacks you can do in the room.

The hacks below will reduce echo, reverb, and noise travelling – plus will absorb some frequencies of sound giving you a far better environment.

  • Use soft furnishings in the room to absorb noise
  • Use wall-hangings to absorb noise
  • Lay carpet in the rooms to reduce and absorb noise

Final Thoughts

Building my own sound maze has been one of the most rewarding projects I have done in my own home as part of my larger soundproofing project.

It’s cheap, easy to assemble, and only really takes up time.

If you do decide to do it please do send me some photos and tell me what results you managed to get in reducing the noise coming through your vents.