DIY Soundproof Window Insert Plugs

person measuring for a window plug

Although windows are a great way to bring natural light into your home, they do not block sound very well. Especially through single-pane windows, you can easily hear your loud neighbors. Because windows aren’t great sound barriers, you might want to build a soundproof window plug.

A window plug can effectively block sound waves from entering your house. Let’s talk about everything you’ll need to build one yourself.

Why Won’t You Find a Window Plug on Amazon or at Home Depot?

You might be tempted to skip the hassle of making a window plug and just purchase one from a store. Unfortunately, you won’t find soundproof window plugs for sale at places like Home Depot or Amazon.

Major retailers don’t sell window plugs because all windows are different. In your home, your windows will be unique, with their own size and shape. Window plugs have to be custom-sized to fit your specific needs.

Because of this, we’d recommend making one yourself. This process is fairly simple and inexpensive.

The best part of this DIY project is that you can fully customize your window plug. You can install whichever sound-absorbing material you like and cover it with a fabric that matches your home decor.

Rest assured that many people have successfully completed this DIY project, so you can too!

You Will Need:

  • Tape measure
  • Wood planks
  • Foamboard
  • Foam tape
  • Fiberglass Insulation
  • Mass loaded vinyl
  • Saw
  • Drill
  • Screws
  • Utility knife
  • Fabric


  • Handles

The best wood to use to build a window plug is Medium Density Fiberboard. Although you can also use plywood or OSB, MDF will do a better job at blocking sound waves.

In this project, you’ll need the best soundproofing materials, and you can’t go wrong with MDF. At Home Depot, a single 2 x 4 costs around $10. The amount you need will depend on the size of your window, but four boards will probably be enough.

You’ll need foam board to fill in the wood frame and create a surface to lay the insulation. This is around $15 for a 4 x 8 board.

Fiberglass insulation will help your window plug be as soundproofed as possible. A roll of insulation will cost less than $10.

You can also use mass-loaded vinyl to layer underneath the insulation. This will be durable and flexible, making your window plug last a long time. This will be the most expensive item on this list, costing $50-$100 depending on the size you need.

This entire project will likely cost less than $100.

Create Your Window Plug

The basic construction of a window plug is a wooden frame that is filled with insulation and other soundproofing material. This is one of the most effective ways to soundproof a room because it adds an extra barrier to absorb outside noise.

A DIY window plug is exactly what you think it would be. It fits tightly into the alcove of a window, creating a great seal to deflect sound waves. Whether you want a quiet space for an office, bedroom, or nursery, a window plug is a great option.

Once you’ve made a DIY window plug, you can leave it on the window permanently or remove it whenever you’d like. If you want to move it daily, you can attach handles to ensure an easy removal process.

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There’s no need to worry about doing this project yourself. Anyone can make their own window plug by following these steps:

Step one: Measure your window. Don’t use the outside of the window frame for your measurements. You should use a tape measure to find the exact size of the inside of the window. This way, the plug will have a perfect fit.

Step two: Double-check your measurements. Make sure to check both sides of the window, because it might not be level. Measure the depth of the window as well. The frame needs to fit snugly into the window for maximum soundproofing.

Step three: Buy your supplies. See the list above for all of the materials you’ll need.

Step four: Use a saw to cut the wood to fit inside your window. There should be four pieces that will outline your window plug. Make sure to measure twice, and cut once!

Step five: Construct a wood frame. Attach each piece of wood to make a rectangle, the same shape as your window. Use a drill to screw these boards together.

Step six: Attach foam board into the wood frame. Use a utility knife to cut to size. This makes a flat surface to stack all of your soundproofing materials.

Step seven: Place mass-loaded vinyl and fiberglass insulation on the side that will face the room.

Step eight: Seal the edges with foam tape or soundproofing glue.

Step nine: Cover the entire frame with fabric to give it a cleaner look. You can choose any fabric design that appeals to you and flatters the interior design.

Step ten (optional): Attach handles to your DIY plug to easily move it to and from the window. If you are moving the plug daily, you won’t want to skip this step.

Step eleven: Insert the plug into the window and enjoy your soundproof room!

For extra soundproofing, you can install new weather stripping to seal any air leaks in your window. This not only helps to reduce sound waves but also helps your window plug fit nicely.

Final Thoughts

If you are hearing a lot of street noise, loud neighbors, or construction, this may be coming through your thin single-pane window. Although you can buy soundproof curtains, blinds, or sound absorption sheets, there are better soundproofing methods.

You can easily fight noise pollution by building a window plug. This is installed to fit snugly into a window, effectively soundproofing a room.

Although there are very few companies that make customized window plugs, you can easily make one yourself. The basic construction is simple: a wooden frame with layers of soundproofing material.

This process may take more effort than other soundproofing methods, but can be much more effective. With a window plug, you can enjoy a much quieter living space.

  • Gregory A Seely
  • Gregory A Seely

    Greg is a self taught home renovator and writer for RenoViso. His shares his experiences with Southern Living, Traditional Home and other publications.

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