How To Soundproof Air Vents: 8 Simple DIY Methods Of Noise Reduction

soundproof air vents

It’s almost impossible to get adequate sleep or work in your home office when you have a noisy outdoors. If you are in this situation, you must have tried solving this problem by insulating the windows and soundproofing the doors. Maybe you have also purchased the best soundproofing curtains you can find. Still, they have all proved ineffective due to the disturbing sound that passes through your open above-door vents.

Sound can enter your room even after covering the doors and windows through the above-door air vent, and by simply missing the above-door vent, your efforts to soundproof your room are a waste.

Blocking out the noise by covering the air vent with a soundproof vent cover is one of the ways to solve this problem, but this is not the best way to solve the issue of an above-door vent sound because not only does it restrict the airflow in the room, it interrupts the overall ventilation.

Blocking the airflow in the room can result in health complications, mold growth, cooling problems, and unwanted odor.

Can You Soundproof A Vent Without Messing Up With The Airflow?

The simple answer is no. Every soundproofing material out there restricts airflow in one way or another, and air is the primary carrier of sound.

But notwithstanding, a few things can be done to stop noise from entering through the above-door vents without entirely blocking the airflow. Your soundproofing needs and objectives will be unique depending on your reality.

A choice can be made from many options depending on your soundproofing needs and objectives.

Examine The Air Vent

One major step should be taken before going ahead to soundproof the air vent that most people overlook, for example, Inspecting the air vent. Before you can choose the proper noise reduction technique for your needs, it is important to understand:

  • The goal of the air vent.
  • The shape of the air duct.
  • The number of walls/surfaces in the air path.
  • The material of the air vent.

Types Of Air Vents

Air vents are broadly classified into – Ventilation vents and (HVAC) Heating, Ventilation, and Air Conditioning vents.

Ventilation vents: Ventilation vents are used for cross-ventilation between two rooms and are mostly found above the doors.

HVAC vents: HVAC vents are used for temperature control within an infrastructure.

There might be condensation if the door vents are blocked without adequate insulation.

The pathway air and sound will travel is determined by the shape and length of the air vent. Longer vents are always less noisy than the straight and short vents.

The airflow will be restricted if there are enough barriers/walls in the path of sound. The sound waves lose energy when they bounce on the surfaces, therefore resulting in the reduction of noise.

Using aluminum and steel materials leads to louder echoes, creating more noise in the room. Additionally, gaps and leakages in the air duct network can result in loud and hissing noise in the system, which should be treated individually.

It is important to recognize and understand the ductwork issues to choose the soundproofing method to tackle them efficiently.

Best Tips For Soundproofing Your Air Vents

While working on my home, I faced the problem of noise coming from the vents, but I solved it after trying many things. I will share what I tried, which helped me soundproof my vents.

1. Create A Sound Maze Within The Air vent

Blocking the above-door vents will not be a good thing to do if your house usually gets very hot and uncomfortable during summer without ventilation. In this case, creating a sound maze will be the best possible alternative.

A sound maze allows the air to continue flowing freely through the air vent while using up the energy of the sound waves and deadening the noise effect. Many barriers in the sound path force the air to start moving in a zig-zag pattern in the air vent.

This method covers the surfaces with sound absorbents, and the sound bounces off the surfaces. It effectively reduces the noise without the airflow being restricted that much.

How To Build An Air Vent Sound Maze: An Easy Guide

Building an air vent sound maze becomes easy once you have the right materials and instructions ready.

Things you will need:

  • Step ladder for a high-up vent
  • A screwdriver or a drill
  • Plywood Sheet that is at most 1/2 inch thick.
  • Acoustic Foam
  • Small Wood Saw
  • Small Screws
  • Utility Scissors or Knife
  • Measurement Tape/Scale
  • Strong Adhesive like Gorilla Glue

These tools and materials are relatively easy to find, and you can find them online or in your local hardware store. You should choose an effective workplace after getting all the materials and equipment. Choosing an effective workplace will help avoid damage and injuries using a wood Saw and glue.

How To Create A Simple & Effective Sound-Maze

Step 1: Measure The Air Vent Size

Use the step ladder to reach the vent if it is high up, and use the screwdriver to lose the screws. Measure the air vent’s dimensions with the measuring tape. After taking the measurement, the overall length of the vent will decide how many barriers are required in the maze.

Step 2: Cut The Plywood To The Same Size

Map out the duct’s measurement (width x height) on the plywood sheet not more than 1/2 inch thick. After cutting out the first piece, check if it is perfect for the air vent. Note: The first piece should be the same height as the air vent but 30% slimmer than the whole vent, enabling the air to pass through. Cut the plywood into four pieces. The length of the air vent will determine the number of walls you should make.

Step 3: Glue The Acoustic Foam Over The Plywood

Get your acoustic foam and the glue. Cover each of the plywood pieces you have cut with acoustic foam. Covering them with acoustic foam will prevent sound echoes because of acoustic foam’s ability to absorb sound. The acoustic foam will absorb the sound energy, reducing the weight of the noise coming in through the air vent.

Step 4: Fix The Plywood Inside The Air Vent

After cutting the plywood into pieces and covering them with acoustic foam, the next step is to arrange them inside the air vent. When placing them inside the air vent, you should position them on alternative sides to form a maze.

Use adhesive glue while positioning the plywood to make it firm, and there should always be at least 1 inch of space between each plywood wall for enough air circulation.

Step 5: Cover The Interior Of The Air Vent With The Acoustic Foam 

Once you are done fixing the maze walls, ensure you cover every side of the air vent with acoustic foam for effective sound absorption. Attach it firmly using the glue. If you do this right, it will further reduce the overall echo inside the vent.

The last step is to screw back the air vent cover with a screwdriver.

2. Use Acoustic Foam To Reduce Noise

If you have been in a studio, cinema, or theater, you must have encountered acoustic foam. Acoustic foam has a polyurethane-based material like polyester, extruded melamine, and polyether.

Though the primary aim for designing acoustic foam isn’t to damper noise but to improve sound quality in a closed room by absorbing the echo since the walls of the air vent are mostly metals, the reduction of the echo caused by the bouncing-back of the sound can reduce the overall noise.

You can easily purchase different types of acoustic foam online for about $1.5 per square foot or at your local hardware store.

How To Use Acoustic Foam To Reduce Noise

  • Open the air vent by using a screwdriver to lose the screws.
  • Use a layer of acoustic foam to cover the whole interior of the air vent.
  • Use an adhesive to fix the acoustic foam layer to the sides of the vent.
  • Close the air vent by tightening back the screws with a screwdriver.

After successfully installing the acoustic foam in the air vent, it will help to trap and reduce the sound wave energy, therefore numbing the noise.

3. Cover The Vent With Soundproof Curtain Covers

One of the primary roles of an above-door air vent is to maintain the room temperature in the summer and allow ventilation when a room is closed. Therefore, permanently blocking the air vent may do more harm than good in the long term. 

In this situation, using a soundproof curtain or blanket to cover the air vent is the right thing to do.

Covering the air vent with a soundproof curtain or blank is a straightforward and cheap way to reduce the noise coming in without distorting the overall aesthetics of the room.

How To Cover The Vent With Soundproof Curtain Covers

  • Get a curtain rail. You can purchase it online or at any interior decor store in your local market.
  • Install the curtain rail on the wall above the air vent.
  • Then, hang your soundproof curtain on the rail.

If you don’t have access to a sound-resistant curtain, you can use a curtain made of thick and dense material that has multiple layers. 

For best results, let the curtain drop to the floor from the curtain rail above the air vent, and on hot days, you can open the curtain, and you will have enough airflow.

Here is another helpful hack you can also try that can temporarily cover the air vents that are closer to the floor. Instead of covering the a with air vents with a curtain, you can try blocking them with soft furniture pieces like a beanbag or sofa. The thick, echo-absorbing fabric will absorb the sound waves and efficiently reduce the noise in the room.

4. Block The Air Vent With A Dry Wall

In the 3 techniques, we have discussed ways to reduce the noise coming into your room from the air vent without completely blocking the air vent. However, if you want to achieve total silence, for example, if you are setting up a studio and you need to keep the noise away, you can remove or block the air vent completely.

If heat isn’t an issue for you because you have a way to maintain a reasonable temperature in the room by using an air conditioning system during the summer and you have adequate ventilation, then the best option is blocking the air vent entirely. 

How To Block The Air Vent With A Drywall

The procedure to block the air vent with a drywall is relatively simple:

Step 1: Open Air Vent

Open the air vent with your screwdriver, measure the dimensions of the air vent, and cut a wooden plank using the measurement. Afterward, fix the wooden plank at the beginning of the air vent.

Step 2: Insulate Ducting

You can fill the air vent with insulation like gypsum or drywall. You can still use it to close the air vent with an extra wooden plank and then fill it off with drywall.

Step 3: Blend Wall With Gap Filler

The air vent should be blended with the wall after the filling using a wall-based adhesive. After it dries, use sandpaper to mix it with the wall texture, and then paint the air vent to match the wall.

It is best to consult a professional before sealing off an above-door air vent if the air vent is part of the HVAC system in the house construction. That will help you prevent ventilation issues.

5. Fill the Air Vent with a Soundproofing Sealant

If you find the above methods of noise reduction tiresome, then you should use a soundproofing sealant to fill the air vent. Using an acoustic sealant to soundproof an air vent is a less tedious option. 

Some foam sealants or gap fillers expand to fill the surface when applied. You can check out Touch n’ Foam Max Filler or Great Stuff-Gap Filler.

Using an acoustic soundproofing sealant provides the same result as drywall fillers. These soundproofing sealants are airtight and water resistant and can also be blended to the wall texture easily with sandpaper and painted to match the wall perfectly.

A sealant will perfectly take care of the condensation caused by a working HVAC system because of its water-resisting ability.

How to Fill the Air Vent with a Soundproofing Sealant

  • Loosen the screws and remove the duct cover
  • Apply the soundproofing sealant on the air duct and fill it
  • Fix back the vent cover, and you are done.
  • It only takes a few minutes to complete this process.

6. Cap the Air-Vent Temporarily

If the noise coming in through the air vent is beyond management, but there is adequate ventilation in the room, you can build an easy-to-install temporal cap. The plug can be removed and only used when needed.

How to Cap the Air-Vent Temporarily

  • Remove the air vent cover screws with a screwdriver
  • Measure the total dimensions of the vent
  • Map out the dimensions on a 1/2 thick plywood and cut it out with a wood saw.
  • Place the piece of wood you have cut out inside the air vent and bind it with waterproof tape.
  • Optionally, you can apply a weather-stripping take on the inside edges of the air vent cover to ensure it is totally soundproofed.

Soundproofing HVAC Vents

1. Use Flexible Ducts, Duct-liners, & Soffits

Flexible ducts

Though flexible ducts can reduce the amount of sound leaking from your air vent due to their bendy nature, you should only use them when important.

The flexible ducts work by creating bends in the duct, making it more difficult for sound to travel because the sound is absorbed partially any time it encounters a bend.

Note: Due to the bending of the duct, there may be small breaks in them, which may cause leakage of sound and jeopardize the effectiveness of the flexible duct. Therefore, to avoid sound leaking from the duct, only use quality flexible ducts like Dundas Jafine.


Installing duct liners can be an easy and cheap method of insulating sound due to their insulation materials that reduce the sound vibrating in the air vents.

Duct liners have a double-sided liner and are fixed to the internal walls of the air vent to avoid the blowing of glass wool fibers into the room by the liners.

The effective soundproofing duct liner I highly recommend is Reflectlix; it is cheap and of high quality.


Insulating soffits can be used to cover the air vents if they are directly exposed to disturbing sound. A typical soffit with a layer of MDF board with insulating material will be used to solve the problem. To achieve a better result, the flexible duct inside the soffit should have many bends.

If the room requires a high level of soundproofing, you can add layers of drywall with Green Glue

2. Upgrade your HVAC System

Sometimes, you have to check your HVAC system for leakages and gaps in the ductwork; it might be the reason for the disturbing noise, or the HVAC system might just be entirely old. 

The best thing to do in this case is to get a professional to renovate the entire HVAC system, ensuring sound reduction and adequate air inflow and circulation within the room.

Changing the entire ventilation system may be costly, but investing in it is beneficial in the long run.


It may be a waste of resources if you soundproof your room and ignore the air vents. Whether it is your bedroom or basement room, everybody’s soundproofing needs are different; therefore, the suitable options will differ.

No matter your soundproofing problems, they can be solved with one of the solutions in this article; you have to choose the best solution based on the requirements of the room, your soundproofing needs, your budget, and the time and effort required.

If an air vent is not in use, the best option is to close it completely.

With these solutions discussed in this article, you are just a few steps to achieving your desired level of silence without spending a lot of money. Good luck.

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