How to Soundproof a Window A/C Unit in 6 Easy Steps

How to Soundproof a Window A/C Unit in 6 Easy Steps

Air conditioners are essential in our lives especially during the summer season. And For some of us, who own a window ac unit, know that with its sweet relief of cold air, the issue comes when it makes noise. In this case, you need effective and reliable ways to soundproof a window A/C unit, reducing unwanted noise successfully.

However, if you don’t have a supportive guide, someone might rely on ineffective methods, as you will come across countless and different methods out there. Fortunately, I have deep-researched the affordable, dependable, and practical ways for soundproofing our window ac units tested and approved to meet your needs and expectations.

Soundproof a Window A/C unit with a Soundproof Box

Like you might have of the air compressors and generator soundproofing boxes, you can also build one for the air conditioner unit. Remember, this box should have ventilation; fail to that it might overheat, killing your air conditioner unit. Follow the below guide to building an A/C soundproofing box:


(a) Mass loaded vinyl

(b) Medium-density best fiberboard

(c) Acoustic caulk

Step 1: Take measurements

This is the first thing to do when building you’re a/c unit box. Thus, ensure the measurements are exact to that of your air conditioner. However, give about one-foot room right on top to let an appropriate airflow after you have measured the front, back, and side of your box.

Step 2: Cut the box

Utilize a pencil right on your fiberboard to precise trace where you intend to cut. Remember, making a mistake can mess the whole procedure. At this point, use a saw to successfully the box.

Step 3: Arrange the box together

Using L-brackets and glue plus screws, consider putting the box together as possible you can. And if possible, don’t leave any open gaps in between the pieces of the fiberboard.

Step 4: Make two exact ventilation holes.

As we discussed earlier, airflow is vital to keeping your a/c motor cool. Thus, make one hole right on the top panel while another one on the back or front panel. And the holes are supposed to face away from where you intend to keep away sound from reaching.

Step 5: Use mass loaded vinyl to line inside the box

At this point, cut the MLV, adhere it inside your box utilizing nails, green glue, or staples. Besides, it’s essential to cover every surface to avoid leaving spaces.

Step 6: Utilize the acoustic caulk to seal the gaps effectively

Acoustic is meant to prevent any sound from exiting via the remaining small gaps between MDF or vinyl. Consider applying a generous amount.

Step 7: Place your box right on top of the air conditioner unit

All that is left is installing the box to A/c and enjoy the magic results.

If you want an more in-depth article on building a soundproof box checkout my article: How to Build a Soundproof Box for a Generator

Lower the vibration noise

Vibration generated right by the window air conditioner is easily transmitted to the wall or ground. However, this also depends on where your unit is mounted, specifically if you have not stored it appropriately. In this case, consider checking if it’s appropriately leveled and also if the screws are tightly in place.

For example, if your air conditioner is right mounted outside your bedroom wall, the vibration effectively reverberates, generating unwanted noise inside your bedroom. Thus, opt to change your unit’s specific location and place it right on the top of anti-vibration pads to reduce the vibration transmitted to other related structures.

Use the acoustic a/c blanket

The straightforward way of soundproofing your loud window AC unit is via using the acoustic blanket. Adding additional barrier absorbs and blocks the sound to aid quite the air conditioner. Soundproofing blankets are outstanding at this specific point, specifically the ones designed to lower air conditioner noise.

They are easy and affordable to install, and above all, they are effective. Besides, when you decide to use such a blanket, please avoid using your unit for every hour since it might overhear as you blanket over its airflow. However, due to its affordability and effectiveness, you can never go wrong within.

Install the sound-absorbing fabrics

In essence, you will love how acoustic foam’s densities help absorb lots of unwanted noise generated from the a/c unit. Get three and four pieces of this specific acoustic foam and adhere it to the wall behind the unit to lower the excess noise.

To effectively install this, someone will require a glue spray, and around 20 seconds of you will have completed it. Besides, some individuals might want to take this specific step further by adding the mass-loaded vinyl right on top of acoustic foam, followed by acoustic foam on top of vinyl again.

And since the MLV is a bit heavy, the adhesive along might not cut it, so the experts commends using the screws and nails to adhere it appropriately.

Work on inner unit

When the noise from the a/c unit is too much and disturbing, you got two fundamental ways to quiet it:

Step 1: Build the sound dampener.

This will absorb much a/c sound and make it manageable. In this case, you only require medium-density acoustic foam, fiberboard, plywood, and some effort.

Step 2: Stop the A/C’s flaps from operating.

The air conditioner flaps generate a lot of unwanted noise, more than you can imagine. Thus, ensure to set perfect settings in a beneficial way that they will stay still. However, if you get some challenges on removing it, consider reading the manual from the producer.

Soundproof the windows

While trying to soundproof your air conditioner, you also need to consider soundproofing the windows because this is where a lot of sounds come in. And to successfully soundproof the window, consider using the below techniques.

Step 1: Weather-strip the windows

This is one of the most affordable, effective, and quick methods to apply when soundproofing the windows and doors. Apply the weatherstrip that forms an air-tight right between window and frame.

Step 2: Install the door sweep.

A door sweep is designed to cover any gap left-right between the floor and door, decreasing the excess noise.

Step 3: Install thick curtains on windows

Acoustic curtains will block 80 percent of noise which is a fair amount. Ensure your curtains go from the ceiling to the floor and some couple of inches past the window sides.


Soundproofing window A/C is not a challenging process provided someone got a comprehensive support guide. And I have picked the easy, effective, and affordable ways on the above guide to successfully soundproof your window a/c unit. Good luck