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


4.48 Average 1399 Reviews logo

Fayette V

The inserts provided immediate results for the better. The inserts a virtually invisible which was better than expected. The biggest challenges were getting the accurate measurements which I Dow was helpful with and repositioning the blinds. Everything has worked out. We are planning to do this with other windows

Posted 3 days ago

Jamie W

We were excited to receive our Indows, but once we got them in, we were blown away! They match our woodwork almost perfectly. Installing them was far easier than we had anticipated, and we were immediately impressed by the noise reduction, as well as the ability to reduce the impact of the windows on our indoor temperature! Couldn't be more pleased and very excited to be able to add "custom" shapes for the top of our lancet windows.

Posted 1 week ago

Mark H

The acoustic indow window worked better than I expected at blocking out noise. The only thing I didn't like was the shipping company (T-Force Freight). The shipping company was difficult enough that I decided to rent a U-Haul and pick it up at their warehouse.

Posted 2 weeks ago

Venkatesh G

Indow solves my noise problem due to highway traffic. I recommend this company for noise reduce solutions.

Posted 2 weeks ago

Thomas R

The process was simple and easy. I was a little nervous having to measure everything myself...but I got the inserts and they fit in our windows perfectly without any hassle. 1000% recommended.

Posted 2 weeks ago

Dan E

As always with internet purchases, I was holding my breath on my recent purchase of inserts! However, everything suggested by everyone I spoke to via telephone, email and text, was verified when I received and installed my inserts!!! Nothing short of phenomenal; fit, sound deadening qualities, (yet to discover energy savings), and customer service is excellent!! I highly recommend this company and product!!

Posted 2 weeks ago


Good quality window inserts. Easy to install. Unfortunately, doesn't do much to block road noise that I was hoping it would help with. Website is clear on the uses so I can't say it was false advertising, just buyer error.

Posted 3 weeks ago

Tommy J

We ordered 4 Indow Window inserts to see how they worked on our steel casement windows. We are very pleased with the fit and finish, and especially the improvement in wintertime comfort. Steel casements present challenging issues when trying to improve efficiency. The only downside for our installation is it required the removal of the locking and operating hardware to work in concert with our window treatments. The attached photo is during installation with Indow inserts installed on the two left pair; not yet installed on the two right pair. Pretty minimal visual difference! I'm now ordering 17 more inserts for the rest of the house.

Posted 3 weeks ago

Catherine L

Our acoustic window inserts have definitely reduced the amount of street noise coming into our apartment. While we can still hear the train as the engines pass by the noise from the train cars is very muted. Likewise we still hear the drunken club patrons yelling, but it no longer seems like they are in the room with us. Our big negative would be that the blinds we enclosed in the space between our single pane and the insert melted and warped within the first week. I don’t think there was any mention in the directions about the possibility of heat build up and potential consequences. That might be good for people to know.

Posted 3 weeks ago

John W

Finally, a solution that doesn't break the bank and allows you to keep your existing windows. We bought ours primarily for additional soundproofing as our builder used dual-pane glass. It makes a measurable difference - 20 dB. The bonus is the insulation value. It's been a mild spring and our main bedroom at the front of the house facing the morning sun is much cooler. I suspect it will be warmer in winter as well. If you follow the self-measure and installation instructions to the letter, they go in easily. We have floor-to-ceiling windows, so we had massive inserts, but it was still manageable for two people.

Posted 3 weeks ago

Jillian G

The measurement process was overly complicated - I understand the desire to get a tight fit into not perfectly square windwos, but a 17 page manual for something you can accomplish with math felt unnecessary. I also found the interface to be a bit challenging to work with when inputting fractions that necessarily had to be rounded but the system didn't like my entry. Otherwise, the inserts themselves fit well, very tight, noticeable noise reduction. I am so satisfied with them that I am considering placing another order (depending on whether I want to also spend the money to change window treatments).

Posted 4 weeks ago

Michael M

What a great option for old homes with drafty windows! Our home's windows are so drafty that the curtains in our bedroom would move/blow when it was windy out. The communication with Indows was excellent, and our questions were answered promptly. We thought the measuring process would be a pain, and we were worried we would not be accurate enough, but the kit they sent along with the instructional videos made it very easy. The Indows were delivered in a large wooden crate, and they made it through shipping unharmed (just some dirt marks on the silicon tubing, most of it came off with Castille soap, but some dark smudges did remain on the white tubing--our only disappointment). Our windows are huge, so we installed the little safety chain provided and inserting them was a 2 person job. There was a little bit of a learning curve with the first Indow, but we can take them in and out fairly easily now. The fit was perfect, and we noticed a difference in the temperature of our home right away. Our house stayed warmer, our furnace ran less, and our curtains are no longer blowing in drafts. The product looks great, and blends right in with our woodwork! We will definitely order more for the few windows we didn't do, and we would recommend this company and product to anyone.

Posted 4 weeks ago

Lisa I

They really work! While I still hear traffic (mostly trucks and motorcycles) normal car traffic is virtually silenced. I'm still not able to sleep in the room because we get so many trucks I am able to use this room as an office space now, which was my goal. This room was once the noisiest room in my house and now I enjoy coming up here to watch tv. Thank you!

Posted 4 weeks ago