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5 Simple DIY Soundproof Window Insert Plans

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If you’ve soundproofed your walls and added acoustic treatments, but still have a noise issue, many times you’ll find the windows in your room are the culprit. Glass is a terrible insulator, and sound loves to transmit from outside through the glass panes and frames.

Professional soundproof windows work great at reducing noise, but these can be insanely expensive since nearly every window insert has to be custom-made to properly fit your specific window.

Thankfully there are ways to build a soundproof window on your own, even on a budget. Just check out these five unique ways to make your own DIY soundproof window insert.

What is a Soundproof Window Insert?

A soundproof window plug is a foam, acrylic, or wooden insert that fits inside your window frame and deadens outside noise from traffic, kids playing in the yard, construction, or airplanes flying overhead. It’s a great idea for your home theater or a recording studio. Soundproof window plugs can also help keep noise within your room, such as a practice studio. Window plugs can be permanently installed or removable.

Pros & Cons of a Window Plug

The many benefits of window plugs include…

  • Reducing sound from entering/escaping your room. Obviously, the chief benefit of using window inserts is to keep sound in or out of your room.
  • Help reduce heat transfer. A good side benefit of using window plugs is that they can help significantly with your energy bills. The plug helps to seal any small gaps in and around the window frame. Glass, as we mentioned, is not a great insulator. By covering the windows snugly, you’ll keep heat from escaping your rooms in the winter and keep the sun from heating up your rooms in the summer.
  • Improves air quality. By sealing the window, your window plug helps to keep out allergens and other particles that can cause help concerns in some people. They will also help to reduce the dust circulating in your home.
  • Reduces fading. UV rays can make your furniture, rugs, books and other belongings look dull and old before their time. Window plugs not only reduce sound, but they prevent UV rays from entering your rooms from the windows.

However, there are a few disadvantages to using window plugs to block sound waves from entering (or exiting) your room. Among these are…

  • Less light. By putting up a window plug, you are blocking at least some of the natural light from entering your living space. For some rooms, such as a home theater, that isn’t much of a problem. However, for other rooms, such as a home office, less natural light can make the space less appealing and less conducive to productivity.
  • Expense. Custom-made window plugs can be very expensive. That’s why we’re going to discuss DIY window plugs in the next section.
  • Aesthetics. The look for some window plugs leaves something to be the desired decor-wise. However, with window plugs, it’s easy to add fabric or vinyl to the side that faces into your room to make the plugs more visually pleasing…if you opt not to use acrylic.
  • Hampers the function of the window. Lastly, you won’t be able to open the window while the window plug is in place. That can affect the comfort level in the room.

1. Second Skin Window Insert Kits

If you’d like to insert window plugs in your windows without having to create the entire project from scratch, Second Skin makes it easy with Fantastic Frame Window Inserts. This is a DIY kit for window plugs that are easy to install. The company claims that these window plugs will pay for themselves in 12-18 months in savings on your energy bill.

These kits can be made for virtually any size window. The kits include four metal “L” angles, plexiglass sheets, screws, insulating foam, and window cleaners. You’ll need an electric drill, screwdriver, tape measure, tin snips, and some insulating foam. Complete detailed instructions are included with each kit.

2. Make your own “Indow” Window

Another good way to soundproof your windows without spending a lot of money is to create your own “Indow” window. Indow is a brand name that sells somewhat pricey custom-made window inserts. They are great, but you can create your own with just a little time and only about $120 in supplies for a large window. Here are the steps:

  1. Measure your opening carefully. Using a laser measuring device, measure the inside of your window opening (twice) to get the size for the piece of acrylic you’ll need. The acrylic is going to take most of your budget, so you don’t want to make a measuring mistake.
  2. Purchase your supplies. You’ll need a piece of acrylic with a thickness of about 1/4″ or 5mm. There are a variety of grades of acrylic. The higher the grade, the higher the price. We recommend using one of the higher grades, as it will last longer, filter UV rays better, and be less likely to yellow as it ages.

You’ll also need commercial-grade adhesive and foam padding to fit around the acrylic. We use baby bumpers. This product comes in a roll and is available in a variety of colors.

  1. Attach the foam to the acrylic. Although the baby bumper foam comes with a strip of self-adhesive, ignore this. It isn’t strong enough for our project and will just gum up the works. Instead, apply the commercial-grade glue carefully and attach it to the edges of the acrylic. You’ll want to miter the corners to make sure that you don’t have any gaps.
  2. Fit the “Indow” in your window space. After the glue dries, you’re ready to carefully fit the “Indow” into the interior of your window frame.

You can expect around a 15 dB reduction in outdoor noise. Your room should be a lot warmer, also.

3. Soundproof Window Panel

Soundproof window panels from Trademark Soundproofing are another easy way to keep your rooms quiet without spending a fortune. Installing these panels is easy. All you’ll need is a tape measure, pencil, and scissors. It’s also helpful, but not essential, to have a level, staple gun and drill handy.

These window panels come in padded vinyl or clear vinyl. The padded vinyl panels have a neutral-colored quilted fabric on the interior of the panel which improves the look and adds an extra sound barrier. There are also grommets on the panels, so you can install hooks and raise or lower the panels easily to let light in or to be able to open the window when the panels aren’t in use.

These window panels adhere to your window frame using commercial-grade Velcro. To install the panels, you need to clean the area surrounding the window with rubbing alcohol. When that area is dry, attach the Velcro to the wall so that it matches the size of the panel. Carefully attach the Velcro on the interior of the panel to the Velcro on the wall. It’s that easy!

4. Acrylic Window Inserts

This method of making acrylic window inserts is an easy and effective DIY project that will keep your rooms quiet without breaking your household budget. For this project, you’ll need a piece of acrylic for each window, silicone rubber seal, a paper of scissors and (optional) a suction cup tool for inserting the window plugs. (We’ll talk more about supplies below.) The basic steps are as follows:

  1. Measure your windows using a laser measure. You’ll want a measure of the top, middle, and bottom of your window, as well as the left middle and right side of the window vertically. Even window frames on newer homes can vary somewhat in width and length from top to bottom and from left to right.
  2. Allow for the width of the silicone rubber seal. Since you’ll be using a silicone rubber window seal to install the acrylic inserts, you want to subtract that width from the measurement for the acrylic window inserts. The seal measures between 3/16″ and 3/8″, so you’ll subtract 3/16″ from each side (2 times for the vertical measurement and 2 times for the horizontal measurement.).
  3. Order your acrylic using the above measurements from a local supplier. Let your supplier do the cutting, since they have more precise cutting tools and, if they make a cutting error, it’s on them, not you. Expect to pay around $200 for a 4×8′ sheet of acrylic. You can get multiple windows out of that one piece, so the cost of the acrylic translates into around $80-$90 for an average-size window.
  4. Attach the silicone weather seal to the edges of the acrylic, starting with the longer sides. Clip off any excess with a pair of scissors. Make sure the stripping all faces in the same direction.
  5. Insert the acrylic into the window opening. Window suction cups (available on Amazon for around $15) make the process a lot easier.

These inserts are nice because they allow in a lot of natural light, while still blocking drafts and noise. Note: this process works best for windows that have very little variation in measurement between the top and bottom of the window. This technique is not particularly suitable for windows in older homes, where settling has caused asymmetry in the window frames.

5. Build your own window Plug

Another very affordable way to soundproof your windows is to create your own window plugs from scratch, using a wooden frame made from 2″x2″ boards. To do this…

  1. Measure your window opening and create a wooden frame that fits inside the opening. You’ll need to add middle support boards for larger windows.
  2. Cover the frame with fabric. Using a neutral fabric, cover the outside of the frame, using a staple gun to attach the fabric securely to the back of the frame.
  3. Add some acoustic panels to the inside of the panel. Once you have the fabric attached, glue some foam acoustic panels to the inside of the fabric.
  4. Create a fabric hook to back installing and remove the panel easier. To make it easier to put the panel in and out, create a 6-10″ fabric hook in the same material as the covering and attach this to the top, middle of the frame.
  5. Install the panel. The panel should fit snuggly into your window opening, assuming your measurements were correct.

This method should cost around $35 for an average size window, depending on what type of fabric you use.


We hope you have learned that soundproofing your windows doesn’t have to be expensive or complicated. Building your own DIY soundproof window inserts will improve the sound in your studio, enjoy your movies, or just your quiet nights at home!

Tom Davidson

I'm a Design Engineer, husband, and Dad to two. I have a taste for building, playing bad golf, and tackling all kinds of home improvement projects. Read more about the SPT Team.

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