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Soundproof Window Insulation

A window plug is a soundproof sponge designed to block, reflect and absorb sound. We use our 2" thick SoundAway Mat to create our sound-deadening window inserts. Our acoustic window plugs are made of a closed-cell foam material that is moisture- and chemical resistant and is ideal for use in a variety of applications, including as a soundproof studio window insert, for blocking outside noise from your home theater or for incorporating into any room that requires quiet.

Installing our window insulation plugs is as easy as measuring your window, cutting the soundproof matting approximately 1-1/2" greater than the width and 1-1/2" greater than the length, then squeezing it snugly into the window frame. An airtight fit will offer the greatest relief from outdoor noise pollution, including traffic noise, loud neighbors and other unwanted sounds.

How Much Soundproof Window Insulation Do I Need?

To understand how the area you need for your window plugs, measure the width and height of your window openings from the inside of the room. If you need help determining how many feet of our 2" closed-cell foam mat you'll need, provide the dimensions to get a Quick Quote. We'll take your window measurements and tell you how many feet of our SoundAway window insulation you need to complete your soundproofing project. Shop now or contact us for help finding exactly what you need. Avoid exposure to direct sunlight.

How To Install Window Plugs for Soundproofing

In most cases, installation is as simple as cutting the 2" SoundAway Mat to fit inside the window frame. The width and length needs to be cut approximately 1-1/2" greater than the width and height of the window to allow the plug to fit tightly inside the window opening. Windows larger than 3', in either width or length, may require support to keep the plug in place. Below we have outlined the installation procedure for installing noise-reduction window inserts on both small and large windows. Note: A small window is loosely defined as smaller than 3' x 3' or 4' x 2'; anything larger would be considered a large window.

Click here to download installation instructions for large windows

Tools Needed

  • Straightedge
  • Measuring tape
  • Sharp knife or electric carving knife


  • Measure width across the opening of the window frame.
  • Measure length from the base of the frame opening to the top.
  • Measure both ends of the Mat, before cutting, to ensure a straight cut.
  • Trim window plug 1-1/2" greater than width.
  • Trim window plug 1-1/2" greater than length.
  • Insert window plug into window frame.
  • For larger windows, refer to next section.

Installation Specifics for Large Windows

  • For large window plugs, typically greater than 3' in either width or length, add support.
  • Select a lightweight rigid board, such as 1/4"-thick plywood, to use as a backer board.
  • Optional: Install two drawer handles on the backer board for ease of use.
  • Trim backer board 1" less than length and width.
  • Apply adhesive, 3M 27 spray or similar, on the back of the window plug and on the backer board.
  • Center and adhere window plug to backer board.
  • Alternative to backer board: Use one or two tension rods (used to hang shower curtains) across the width along top or bottom or both.