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Return Air Sound Baffle: Causes Of Noise From Return Air Grilles & Ways To Soundproof It

air vent on a ceiling of the room

Last Updated: May 11, 2024

It is normal to hear noises from your air vents.

Well, that is...

If your heating and cooling system are effectively running. 

If the sounds get louder or unusual noises get mixed in, it could indicate any potential problem in the vents.

These loud noises are mostly because of the return air. These noises are nothing to be frightened about. You can easily get rid of this ruckus without spending any money; reducing noise from the return air grille is pretty simple, as we’ll see.

This article includes some hacks to muffle loud noises created by return air.

You can learn how to quiet a noisy air return.

What Exactly Is Return Air?

Most people are not aware of return air before it becomes a problem. 

The air that has completed its movement through all of the air ducts is referred to as return air. It starts off the cycle as supply air from a furnace or air conditioner.

Moving through the ducts, it returns to the HVAC system by specialized return air ducts for further heating or cooling. The supply air ducts are in charge of delivering heated air from the furnace or cooled air from the AC unit to every part of the house through the supply air vents.

While return air ducts pull out the air through isolated vents and transport it back to HVAC or AC units. The air then again circulates through the same pathway continuously.

What Causes Noise From The Return Air?

air vent at the ceiling of home

It is normal to hear sounds from a running HVAC system or AC unit. Though, if you feel like the sounds are increasing and have become bothersome. Any unusual noises can indicate some kind of potential issue in the system.

You must initially attend to the source of noisy supply or return vents.

There can be various causes for these loud noises. The main reason can be insufficient airflow. An HVAC system works efficiently with suitable airflow. If there isn’t much airflow, the system may consume more energy.

That may lead it to become more prone to breakdown and damages.

Numerous things can cause airflow restraints i.e. dirty air filters, closed registers and duct dampers, or debris trapped in the ductwork.

Leaky return ducts may also be a source of these unusually loud, irritating noises. The air starts pulling inside the ductwork. As a result, the air volume in the system is elevated and this will tilt the normal balance.

How To Quiet A Noisy Air Return?

By being familiar with the cause of noisy air return you can easily eradicate the issue. Now you have to learn how to reduce noise through wall specially from return air.

Here are three things I typically recommend you try, in this particular order:

1. Open All The Vents

This should be your first step when you observe the return air vent of the quiet wall air conditioner making noise. One closed vent doesn’t have much of an effect. But if two or more vents are closed, the system will produce loud noises.

Check whether the grills or vent are adjustable or not. If so, adjust the grille to the most open point to amplify the airflow.

Keep on checking the vents regularly to ensure they are not closed. The closed vents will put excess pressure on the HVAC and it will heat up.

2. Clean Your Vents And Ducts

cleaning of air vent

If you are still hearing noises, after opening all the vents you should check the filter. There are many filters in the return air vents. As the air enters the vent dust and other particles are confined in the filters.

These filters when filled with dust particles can clog the air passage.

The system might have a problem pumping the air through these clogged filters. That may lead to a noisier system. For a simple clean-up, use a vacuum to suck the rubble i.e. dust and cobwebs.

For a deeper cleaning remove the grille and filters to thoroughly wash them. Wash all the dust off, so that airflow becomes convenient. After adjusting the clean filters back you can have a quiet return air grille.

If you are still hearing noises, it is recommended to change the filters. Luckily, the filters are cheap, and changing them is quite easy.

3. Get The Right Vents And Grills

After washing the vents, you should check whether the return vents and grills have proper sizes and shapes. 

The vents should have sufficient openings to allow the air to pass efficiently.

If the vents are not of the right size and shape, call in a professional.

4. Resolve Ductwork-Related Issues

Poorly installed ductwork can become leaky. They force a lot of air into the vents that produce whistling sounds. 

The only solution is to repair the ductwork by correcting the poor insulation.

If you have a more extensive system call a professional to overhaul the ductwork. You can line your return air ducts with noise cancellation features. A fiberglass duct liner can diminish all the loud noises.

It should also be noted that the hard ducts are noisier than the flexible ones. But flexible ducts are more prone to bending that may also restrict the airflow. It is better to select a slightly hard vent with optimum size.

5. Call In A Professional

close up of man had installing air vent to the ceiling

If you have completely followed the suggestions above without any success, there must be a more complex issue. Then you need a qualified HVAC professional. 

It can take you a lot of time to indicate the main cause, while the professional can hunt down the issue in no time.

They have all the experience and equipment important to resolve the problem easily. Not only can they give your ducts an excellent clean-up. But also they can optimize the HVAC system to make it function more efficiently, smoothly, and as quietly as possible.

6. Soundproof Your Return Air Vents

If your vents are making a loud noise, without any issue with the sound or volume, you can simply add a quiet return air grille.

You can create a return air sound baffle. Most air vents are loud, as they are not made up of sound-absorbing technology. 

By adding a sound damping layer to the ductwork, you can diminish most of the noise.

You can have an expert add acoustic foam to the vent to muffle the noise.

FAQ Section

Here are some frequently asked questions and their answers in regard:

How do I make my air return quieter?

You can easily make the air return quitter. Initially track down the source of the noises coming from the system. Try the above-mentioned step to muffle the annoying noises. Open up the vents, clean the filter, check for leaky vents or ask for an expert’s advice.

Why is my return air vent so loud?

There are many reasons that the return air vent becomes noisy.

The most common scenario involves a leaky vent. The outside air is forced in, increasing the air volume inside the vent. Air with increased volume is harder to pump and the HAVC system generates more heat. Due to this, it produces annoying noises.

What causes noise from the return air?

The return air can be noisy because of closed or unclean vents. Closed vents build more pressure in the ducts producing a lot of noise. Dirty filters have dust particles that clog the air pathway, making unusual sounds.

How to soundproof air vents?

You can soundproof a noisy air vent when there is no unusual issue with the system. By creating a return air sound baffle you can muffle the loud noises. Call for an expert to add acoustic foams to the vent. You can also make an extra layer of sound-absorbing material.

Thus you can ensure a quiet furnace air intake and exit without much effort, and before we wind up things, check out this helpful YouTube video:


A noisy air vent can be annoying, as they disturb your normal routine. Shushing it down is possible following the above-mentioned basic troubleshooting stages. The steps are quite simple and easy to perform.

Simply cleaning and opening the vents induce a dramatic change to the piercing noises. For excellent results ask for a professional hand, as they are better aware of the issue, and they are better at prioritizing your safety.

Pay attention to these noises, as some unusual noises indicate bigger problems.

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