How to Soundproof a Window Air Conditioner

If you have a window a/c unit, you know that with the sweet relief of cold air, comes a new issue: noise. Trying the little accordion panels the unit comes with or cutting particle board to go around it, you’re inviting street noise and neighbors conversations in for the summer.

soundproof window air conditioner with window insert in large window

So, do window air conditioners and street noise go hand in hand? They don’t have to! We’re here to tell you how to soundproof a window air conditioner.

There are two main ways to soundproof a window air conditioner against street noise using a window insert. Both allow you to remove the window a/c unit and so are perfect for renters or homeowners.

First Way to Soundproof a Window Air Conditioner for Street Noise

There are two main problems with the framing material a/c units come with. The material itself isn’t a good sound barrier, and doesn’t sit flush against the unit, letting even more noise in.

soundproof window air conditioner with window insert

Getting a custom-measured window insert cut to fit the shape of the window a/c unit will block window air conditioner street noise. They are made of acrylic, which blocks better than glass, and surrounded by tubing on all sides. The tubing will press against the window frame and the a/c unit creating a noise barrier that compresses against every open area of your window.

To be able to install this soundproof window air conditioner:

  • The sides of surrounding a/c must be at least 6” wide. Otherwise, the legs of the window insert risk snapping off.
  • Cutting the corners that surround the a/c unit reverses the process we normally perform to create inserts. This increases the risk of tearing the tubing around the insert.
    • Optional: you can leave off the tubing and place weather stripping around the a/c unit.
  • Check for dents in the a/c unit - this can make it harder to create an insert for.

Second Window Air Conditioner Street Noise Solution

Create two window inserts that fit into your window frame without an a/c unit in place. These window inserts will be separated by a mullion. During the summer, remove the lower insert and install the window a/c unit. Place insulation on either side of the air conditioner and use weather stripping to fill the gap between the upper window insert and a/c unit.

You can also use L brackets to keep the upper window insert in place if you don’t want to install a mullion (but mullions have the best noise reduction). If you don’t want to just stare at insulation from the outside of your house, you can decorate it however you want—paint, stickers, glitter—we won’t judge. Just don’t use solvents that will dissolve the insulation.

soundproof window air conditioner with insulation surrounding unit

You create the foam “insert” just like the acrylic panels above. Make a U shape that will go around the a/c unit and fit in the window. Push it in around the unit so it’s snug. You can squeeze it back out when you want to remove the air conditioner. Be careful not to damage the foam or the a/c unit.

Installing Window A/C Unit with Storm Windows

  1. A custom-measured window insert cut to fit the shape of the window a/c unit.
  2. Create two window inserts that fit into your window frame without an a/c unit in place.

Using either of these options to soundproof window air conditioners will help you sleep through the night: you get to keep your cool air and stop the street noise!

We’ve worked with customers who have a/c units in lots of interesting places, even skylights! They don’t always end up with the solution they thought they would, but they end up happy.

Contact us today to soundproof your window air conditioner against street noise.

Customer Testimonial: Blocking Noise from Air Conditioner

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bedroom with window with Indow inserts installed for soundproofing in San Francisco


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Customer Reviews


4.49 Average 1458 Reviews logo

cynthia g

Great product, well made. Helpful staff and great communication



The window fits perfectly and was easy enough to install by myself. It unfortunately does not reduce much noise, if any at all, from outside, that might be something for the more premium versions. I have noticed that it does help keep in warmth however which is nice.


Laura K

They are wonderful and are keeping out the cold air this fall!


Travis P

I love my Indow inserts! The installation was very simple and the Indow team helped me the entire way. I live near a busy road, an interstate, and an airport. Although not unbearable the noise from those aforementioned sources was noticeable (key word "was" :) ). I am so glad I found Indow because their inserts were affordable, not permanent, and easy to install. The Indow inserts significantly reduced the noise! I don't have official measurements but I'd say the inserts cut down at least 50% of the noise which is a huge improvement!


Imogene S

I am a 78-year-old woman and the windows in question are above two sliding glass doors. All 4 are almost 3'x4' in size. I had absolutely no problem ordering and installing them myself. The Indow rep I worked with initially answered all my questions. Indow helped all the way with the measurements, delivered the indows early, and provided detailed instructions on their installation. My only advice to potential customers is to measure thrice and order once. The key to successful inserts is a perfect fit - with the Indow-supplied laser, you can do it!


Tony H

Great quality & service. Inserts are a good fit. Will be able to give better feedback after we have been hit by severe winter weather.


Rex R

Great product, fit and finish was high quality. The difference of road noise was amazing. I rarel. Hear vehicles any more. Before it sounded like they were going to drive theough the wondow. Great invention!


Sally B

The inserts weren’t too difficult to place and have made a huge difference in reducing outside highway noise. Love that they are barely noticeable once in place so don’t detract from the window view or appearance at all.



Wow! A company that is honest and transparent about their terrific product. Thank you! Received my window inserts this morning. They work well cutting road noise dramatically. Easy to install. But most of all doing business with them has been an uplifting pleasure. Warms my heart to see honest,dedicated people making the world a more peaceful place!


Carol K

From start to finish, working with Indows has been a great experience. They made sure that the measurements I took were accurate so that the finished product fit perfectly. The Indows, definitely reduce the sound out on the street. In a small guest room inn our Inn in San Francisco, the need to open the window and air out rooms is a necessity so we will see how suitable the inserts are in the long run.


Mary B

I am very grateful to have found and purchased Indow dor several problematic windows in my 1909 house. Wanting to retain the stained and other leaded design windows but making them more weather efficient, Indows solved the problem. I just popped them in and viola! Service was also terrific. I do have to adjust the seal occasionally on one of the picture windows but it is no problem.


Miriam L

Our 9-pane living room window was letting cold air in, so we purchases 9 Indow Window panels. They were fairly easy to install and have held up for a few years now. They make a huge difference in comfort in the living room. Great idea you had there!


Sam P

The ordering process was smooth and easy. Window arrive we'll packed and clean. Installation was easy but the safety chains make no sense.


Tamara S

I work five nights a week and keep night hours on my days off, so having a pitch-black room is essential to my health and happiness. After reading some reviews I settled on the Indow sleep panels. My house was built in 1901. I have two bedroom windows that are about 6' tall and 3' wide. From the time I got in touch with Indow, through the measuring process, through the production and delivery of my inserts I felt like they were supportive. Reading the installation guide before their arrival was essential in preparing me for the process. I knew I'd need to install window brackets with a power drill and that unboxing the inserts might be a bit of a chore. This made the installation process smooth which I greatly appreciated. The inserts arrived a few hours after I'd worked through the night, so I was ready to get them installed in short order and get to sleep at a reasonable hour that day. As to their efficacy, the panels block all the light. The sound dampening isn't powerful, but I knew that going in as well. The inserts need to sit 4" from the glass for the full dampening effect and mine can only sit at about 2". There is a dampening effect, just not at the 50% noise reduction that they're capable of. The delivery service that shipped to my house didn't call to schedule the delivery as the instructions said they would. That's the only thing that didn't go according to plan, but I was home so it worked out. Other than that one thing, the panels perform as I hoped they would. I'm grateful for my dark room and my consistent deep sleep because of them. I would work with Indow again in the future.


Gregory B

We love our new inserts. All nine fit perfectly in our varied windows and now we can enjoy a warmer and quieter winter. Indow was fantastic to work with through the entire process. Thank you, Indow!