DIY Window Plug: How to Make One Yourself

Window plugs are an excellent solution if you want to soundproof your bedroom windows. They are easy to make and work exceptionally well. You just plug them in a window opening when you want some silence and remove them afterward.

Store-bought window plugs are made out of foam, sponge, or similar porous materials. These are good sound absorbers, but they fall short when noise needs to be stopped. If you want them to successfully block the sound from passing through your windows, you need to install a layer of soundproofing material (mass, density).

Here is a short guide explaining what window plugs are and how to build one yourself in 3 simple steps.

About Soundproof Window Plugs

A soundproof window plug is a type of window covering that consists of foam and soundproofing material; all backed up by a wooden board with handles. It should stop, reflect, and absorb sound. It works like this – a soft foam surface absorbs sound waves and slows them down, then the thick and dense layer blocks and reflects the rest of it.

In most cases, soundproof window plugs are an excellent solution for dealing with noise, however, filling out a window opening also brings some negatives (the window is there for a reason).

The Pros of Window Plugs

  • LOW COST: The number one advantage is definitely the price, especially if you are building them yourself. Just to compare them with soundproof windows which can cost thousands dollars – they will cost you 10 times less (likely more).
  • THERMAL INSULATION: When you block a window opening the thermal insulation ability of the window goes up. This keeps you warm during cold winters, or cool when it is hot outside.
  • BLOCKING LIGHT: Further, an additional advantage of window plugs is the blackout ability. The plugs block out most of the light too, which can be nice if your bedroom is facing a street with lots of shops and bars.

The Cons of Window Plugs

  • NO DAYLIGHT: On the other hand, the fact that they block out most of the daylight can be seen as a negative too. Most of us prefer our living spaces to be bright and not feel like we’re living in caves. Of course, the good thing with the plugs is that you can remove them during the day, but this doesn’t only bring back the light but also the unwanted noise.
  • MAY LOOK BAD: And finally, as I was already talking about living in a cave, a big chunk of foam stuffed inside the window space doesn’t look too attractive – it takes away from the overall aesthetics of a home.

The bottom line is that soundproof window plugs are an excellent temporary solution for spaces like bedrooms, home theaters, or recording studios where you can just plug them in when needed and then pull them out afterward. But if you need a permanent one, then instead take a look at alternatives.

Building a Window Plug: Step-By-Step Instructions

Step 1: Measure the Window Area

The first step is to measure the height and width of your window opening and its depth. To get the depth measure the distance between the window and the edge of the sill. It is essential to get the depth too because it determines how thick the window plug can be.

You don’t want the plug to be pressed against the glass but always leave some opening between them(at least 2 inches). For example, if the depth of the window is 5 inches than the plug can be around 3 inches thick – you know the math. This will create a dead air space between the window and the plug where the sound waves will ricochet and cancel itself out.

About the size, the plug must fit airtight to the window opening without gaps that would noise to sneak in. So make sure it is at least 1 inch larger than the window frame itself (on each side). This way when you push it in it tightly fits the frame and blocks the sound.

Step 2: Get the Tools and Soundproof Materials

Here is the list of what you’ll need (see them on Amazon):

– Soundproof mat
– Acoustic foam
– Wooden board
– Pull handles

Note that for larger windows (ca. 3 feet) with the substantial depth it is advisable to make a frame for foam and mat to sit in. But for smaller windows building a frame is optional, meaning you don’t necessarily need the last two items (wooden board and handles).

Step 3: Build the Plug

  1. BOARD: If you did the first step then you already know the right dimensions for the plug. First draw them out on the wooden board – MDF board (medium-density fibreboard) is a bit heavy, but it works very well. Then cut the board to the right size while making sure it fits the window space as tightly as possible.
  2. SOUNDPROOF MAT: Again cut the mat to the same size as the board. Then stick it to the inside of the wooden board using glue or some other bondage.
  3. SOUND ABSORBING FOAM: You have probably guessed it – in this step you cut the acoustic foam and stick it to the mat. The important thing is to cut it a little bit bigger than the previous two layers to make the plug snug the window tightly.
  4. HANDLES: In the end, you can attach a handle (shell or similar) to the wooden board. It obviously has to be attached to the side that looks towards the room so you can insert or remove it at will.

As mentioned, you don’t need to build a frame for soundproof window plugs that are meant for soundproofing smaller windows. While larger plugs that are lacking support eventually fold and fall out, the smaller ones are much less likely.

Anyway, if you want a professional look and better noise cancellation, build a frame regardless of the windows’ size.


Hopefully, this guide will help you get rid of annoying noises coming through the windows.

  • As you’ve seen, making a soundproof window plug is not hard at all.
  • Before you plug the window you have to take into consideration all the benefits it brings, but don’t forget to also consider the negatives.
  • Be accurate when you are measuring your window and cutting the materials. Make sure that the plug fits the opening perfectly.

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