How to Soundproof Air Vent

The same way that windows and doors allow noise to pass through, air vents do as well. As a result, if you’re going to soundproof your doors and windows, you should also do the same for your air vent.

This article contains some of the most effective ways for ensuring a successful soundproofing project. We’ve considered ways to soundproof non-HVAC air vents and HVAC vents to cater to your specific needs.

Additionally, we’ve listed some factors to consider before soundproofing air vents.

Flanking Noise

You may occasionally hear noises coming into a room from sources other than the wall separating two rooms. This is called flanking noise, and sounds flowing via air vents are a perfect example. Here are some more examples of flanking noise:

  • Noise from the HVAC system
  • Sounds from doors and windows
  • Noise from interconnected floors, walls, and ceilings

However, this article will only discuss soundproofing noise from normal air vents and HVAC system air vents. But first, you need to know some of the factors that affect noises coming through air vents.

Material of the air vent – If the material of the air vent is made of metal, then chances are the sound will bounce back, and therefore, the noise will effortlessly pass through.

The shape of the air vent- Sound travels faster in a straight line. So, if your air vent is straight, the noise will flow through. Some of the noise is likely to be absorbed if there are bents or corners.

The number of walls in the vent – The noise will easily pass through if the vent does not have many walls. The more the walls, the more sound is absorbed.

How to Soundproof Air Vents

Air vents are categorized into standalone and HVAC systems. The standalone ones are usually above a door or a window, and they bring fresh air from the outside.

HVAC systems are categorized into two: transfer vents and return vents. Transfer vents distribute cold air created by the air conditioner into the room’s atmosphere. To cool it, the return air vents take in the heated air from the room’s atmosphere into the air conditioner. This air is then returned into the atmosphere via the transfer vent.

Additionally, to maintain a temperature balance with the rest of the home, the return air vent draws in cold air from the room and warms it.

Online resources abound with advice on how to soundproof air vents. But not all of them have been verified as true by testing. As a result, you should use caution when attempting any of the procedures.

Here are a few safe methods for soundproofing air vents.

Remove the Air Vent and Replace

This method is one of the most effective ones for two main reasons. One is because it is not expensive and is an easy way of soundproofing. Two, it is a guaranteed method that will not fail you.

After removing the air vent, replace it with sheetrock on the two sides of the wall and inside the installation. If you decide to modify the vent rather than remove it, it will not give you the desired results.

You might be wondering what will happen when it is summer and how to reduce the warmth buildup. Well, you can install a soundproof window, such that you will only have to open it to get enough air circulation. Also, with a soundproof window, there will be reduced noise escape.

You will see some people trying to make a sound maze in the vent. That is by using a box containing plywood and maze foam. This is a brilliant idea, as it will absorb the sound vibration. You can try it and see, but you will need a larger box to completely cover the non-HVAC air vent for maximum effectiveness.

Cover the Vent Completely with Soundproof Material.

Let’s say you are not in a position to remove the air vent. Consider covering the vent with soundproof material. You can use MDF or drywall and acoustical caulk. The drywall or MDF will cover the vent, but be sure to add two layers of green glue. The acoustical caulk will seal the layers between the wall and the MDF.

Covering the vent with MDF and acoustical caulk is key. Why is it? You might wonder. They block the gap, preventing any sounds from going through the air vent, and, as you probably know, sound best passes through unsealed gaps.

However, this method has a downside. Covering the vents will keep the rooms hot since there will be no ventilation, especially during summer. Installing an air conditioner or buying a fan are air circulation alternatives.

Improve the HVAC System

Old HVAC systems are highly noisy since they use technology that is now obsolete. Because of the open space, they also create magnified vibrations. As a result, if your HVAC system is old, it is time to replace it.

Purchase one that is current, incorporates new technologies, and is quiet. To your advantage, it saves a lot of energy, which means you’ll spend less money on electricity bills.

Consider the methods recommended below if your HVAC system isn’t too old and you don’t need to replace it.

Put in Duct Liners

They are very cheap and efficient for sound installation. The duct liner contains an insulation material that absorbs noises and sounds vibration via the inner wall of the air vent. It is fixed to the inside of the air vent.

There are several recommendations online for the best duct liners. However, you should try Reflectix on Amazon. It is one of the best and is also affordable. Imagine getting 25 feet roll, for just 30 dollars! This duct will be enough to cover the whole air vent.

Install Flexible Duct

As mentioned earlier, sound travels best on a straight path. As a result, if you install a flexible duct, it will have numerous bends. These bends will soundproof any noises that may emanate from the air vent.

A flexible duct should be utilized only when essential. Because of the numerous bends, they tend to break when they are frequently used. As a result, the sound is leaked. However, if you get a high-quality flexible duct, such as Dundas Jafine on Amazon, you can be assured that it will last longer.

Install Soffits

Soffits are another option for soundproofing air vents because they act as sound insulators. They are composed of MDF and are insulated on the inside. Soffits are commonly utilized in home theaters because they effectively minimize noise.

You can install some layers of drywall between the soffits to improve performance. Join them together using green glue.

If extensive soundproofing of air vents is required, a flexible duct installed in the soffits will come in handy. And, as previously mentioned, the flexible duct will enhance the bends, providing optimal soundproofing.

Make a Sound Baffle

A baffle is a box that causes a sound to travel further, absorbing and decreasing its energy along the way. Consider it a maze with soundproof materials on the inside of the walls. Foam is a good example of the material. As the sound goes through the box, these soundproofed materials absorb it.

It is a very efficient technique for acoustically isolating air vents. However, it can only be used with HVAC systems. The major goal here is to minimize sound, and the tubes are long enough to do that. Standard air vents don’t provide enough room for the sound to travel, thus there isn’t much sound absorption.

Before sealing the box, you might connect a flexible duct along the pathway for the greatest results.

Seek Professional Assistance

If you are not confident about applying any of the above methods by yourself, hire a professional. You can also seek assistance from one of the size and length of your air vent do not fit any of the materials listed above.

An expert will observe the needs of your air vent and advise accordingly. It may be a little more expensive than the DIY approach, but you will be assured of great outcomes.

Things to Consider When Selecting Soundproofing Products.


When it comes to choosing materials, it is important to know that there are four categories of materials. They include;

  • Dampening materials
  • Vibration isolation materials
  • Transmission materials
  • Absorption materials.

Dampening and vibration isolation materials, soundproof solid-borne sounds, while transmission and absorption materials soundproof air-borne sounds.

Therefore, be careful to know the sound you want to soundproof to choose the right material. Otherwise, you might end up picking the wrong material and wonder why it is not working.


Some soundproofing materials thrive well in certain environments while others do not. It would be best if you did thorough research on a certain material and whether or not it will thrive in the air conditions of your room. These are some of the things to consider:

  • The level of moisture in your room
  • The amount of grease or any dirt on the air vent
  • Temperature Levels

Nature of the Sound

As discussed earlier, there are air-borne sounds and solid-borne sounds. Therefore, you should know which type of sound your air vent produces. It will enable you to pick the most effective soundproofing technique.


This goes without saying. You can only use a soundproofing technique that will not cause you to break the bank. However, if what you desire is worth it, you can stretch your budget to accommodate it.

Final Words

In conclusion, soundproofing air vents can be both simple and challenging. This is mostly determined by the layout, particularly in the case of the HVAC system. They are more difficult to install than non-HVAC vents.

Consider the source of the problem before deciding on the strategy you’ll apply. It will be a waste of time if you implement any technique without knowing the origin of the problem.

If you’re dealing with regular non-HVAC vents, it’s better to remove them entirely. However, this may not always be the best option, as some landlords are relentless in changing the property. Also, consider ventilation while blocking or removing an air vent. Perhaps you should install a window.

If you’re dealing with HVAC system vents, the techniques listed above will come in handy. Do not hesitate to contact a professional if need be.


Why does my bedroom door have a vent above it?

During the summer, the bedroom is likely to be pretty hot. The top of the doorway lets air enter through, allowing the area to be suitably warmed or cooled.

What’s the deal with my air vent being so loud?

If the air ducts supplying air are too thin, vents might generate loud whooshing noises. Also, debris can potentially clog the ducts or close one or more vents.

If the vents appear excessively unclean, you’ll need to contact an HVAC company to clean them or, if you can, do it by yourself.

Is it necessary to have a return air vent in each room?

While it is a misconception that air return grilles must be fitted in every house room, more than one of these grilles must be positioned at key locations around the house. You can also utilize the areas in the house where there is a lot of foot traffic or usage.

Is it possible to have return air vents on the floor?

A return air vent can be set up in either of two ways: every room with a supply register will have one, or each floor of your house will have strategically positioned return vents. When return air vents are close to the supply register floor of a room, they significantly perform better.

Is it possible for mice to go through air vents?

Mice are tiny and adaptable, allowing them to easily enter various confined areas, including air ducts. The Centers for Disease Control (CDC) cautions that mice can fit through a nickel-sized hole, and rats can fit through a half-dollar-sized hole.