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How to Soundproof Windows Without Replacing Them

Can you soundproof windows without replacing them?

Yes, you can.

soundproofing windows without replacing them

In this post, you will learn how to do just that with the following conditions:

  • The method should be effective yet economical.
  • We do not want to permanently block the light that is coming into the room.

Our solution should cater to these requirements.

Problems Faced When Soundproofing a Window

You need to know what issues you will be dealing with while soundproofing a window first hand.

Windows are the biggest weak links which allow exterior noise into your home. All your time, effort and money that you spend while soundproofing a house or just a room will go waste if you don’t do anything about the windows.

Sound Leaks

Traffic noise and the neighbor’s dog barking causing sleepless nights? The most probable culprit is that door or window which is leaking sound into your house.

Windows by design have gaps which makes it easy for sound waves to pass through them. The obvious solution is to plug in these gaps which we will come to later.

Poor Noise Reduction Properties

Unlike walls, doors and windows do not have that much mass to block sound from entering or leaving.

Mass is a critical element in soundproofing. Drywall and MDF have a lot of mass and are thus, are more effective in noise reduction. Windows are just the opposite because they are too light for the job.

Another issue is the glass itself which tends to vibrate. This is most noticeable when playing loud music in the room. However, this will not be an issue if you don’t watch movies or listen to music at high volume unless you live close to an airport with low flying aircraft passing over your house.

Soundproofing Windows Without Replacing Them

You may have heard of solutions like replacing the existing windows of your house with thick, double layered windows. But that is not what you want or else you would not be reading this post.

Most homeowners would not prefer this solution owing to the expenses involved. This is neither an option for those living in rented apartments. Hence, soundproofing windows without replacing them is the best way.

Seal the gaps

As brought out earlier, the gaps, cracks and crevices around your windows will cause sound to leak directly into your house. The first and most important step is to seal these. Gaps are mostly found on the edges where the windows come in contact with the walls.

There are a few ways for sealing these like expandable foam and conventional caulk. However, expandable foam can be a bit messy while conventional caulk is prone to cracks in the long run.

The best solution for the task is an acoustic sealant. Acoustic sealants are fairly good at blocking sound and will last for several years. Decent acoustic sealants would cost $20-30 for a 28-ounce tube.

Create A Window Plug

What is a window plug?

In simple terms, a window plug is something which you can create to “plug” into the window from the inside to block sound from entering or leaving the room.

The window plug is detachable, which means that it can be removed whenever you want to use the window to let in light and fresh air.

A window plug can be constructed in 7 easy steps.


Measure the depth of the window sill in order to determine the maximum depth of your window plug. For example, if your window sill depth is six inches, you will want your plug’s depth to be about four inches.

Step 2

Measure the length and breadth of the gap in which the window plug would fit in. The plug will have to snugly fit in, so you need to be as accurate as possible.

Step 3

Build a frame that matches the exact dimensions of your window plug. Make a cross support to strengthen the frame. Use 1x4s or 1x2s, depending on the depth of your sill or any other material to make the frame. Just make sure that it fits in and sits on the window sill. If it snugly fits in, be assured it will not fall out.

Step 4

You will need two half-inch MDF sheets of 1/2 inch thickness. The MDF sheets will be covering the frame to form a box. Cut the sheets to size and attach one of them.

Step 5

Add insulation inside the open box. The insulation must be of low-density fluffy fiberglass which is ideal for soundproofing. Seal the box with the other sheet of MDF when done.

Step 6

Glue a thin layer of felt tape on along the periphery of the frame. This will help in the snug fitting of the window plug and will also avoid scrapes on the window sill.

Step 7

Attach two handles on the front of the side of the window plug so that you can easily mount and remove the plug.

How Is This Effective At Soundproofing Your Window?

  • The MDF box will have a significant mass that will help in blocking sound.
  • The insulation will help in the dissipation of sound energy.
  • The gap between the plug and the window will isolate the two which will be beneficial for soundproofing.
  • The reduction of external noise will be significant but not 100%. This is true in the case of using expensive materials as well.

What More You Can Do?

  • Attach latch locks for added security especially if you have children in the house.
  • You can fix window blinds so that from the outside, the plug is not visible.
  • You can enhance the effectiveness of the soundproofing by adding MDF layers with a noise damping compound like Green Glue.

Alternate Methods

There are alternate methods if you want to avoid the effort of DIY such as heavy drapes or heavy soundproofing material. Be assured that foam and egg cartons are useless.

If your window does not have a sill, you can just cover the window by fixing the plug on the wall.

Read this article for finding out different ways of soundproofing windows.

Final Thoughts

Soundproofing windows without replacing them are definitely possible within a reasonable budget as long as it is approached correctly.

Sealing the gaps and adding mass is the key. For the average person, the method brought out in this post is fairly effective.