Window Soundproofing: 5 Easy DIY Projects

Walls, floors, ceiling.. they’re all important for soundproofing a room.

But the two most important factors are doors and windows. I’ve already addressed door soundproofing in this article.

However, if the noise that is coming from outside of your home is what bothers you the most, then soundproofing your windows is the top priority.

Luckily, there are a few excellent DIY projects that can drastically cut down the noise coming from the window area.

Out of that bunch, here are 5 simple and affordable projects that can be done even by beginners.

You can do all, a few or just one of these things. It really depends on how much noise you’re dealing with and how much time and money you’re willing to inveset.

Without further ado, let’s check out the nitty gritty details!

1. Seal Off Gaps And Cracks

Sound can easily fall through the cracks and crevices in and around the window.

So sealing off these gaps with an acoustic sealant is the first thing you should do.

Adding insulation tape to the area where the window and sill meet will further block off outside noise.

It will also help with temperature insulation, which is a nice bonus.

Your first step in this process is finding any cracks and gaps.

While you could always repair cracks in the windows, sometimes it’s easier to entirely replace a window pane that has a major crack.

Once you’ve determined where the cracks and gaps are, it’s time to to seal off every spot in the window through which sound can freely come enter the room.

Acoustic caulk (the recommended one, not traditional caulking that breaks easily) and high density foam tapes (insulation tapes) are a great choice for sealing off gaps.

2. Hang Thick, Noise Blocking Curtains

Although they are not 100% effective, soundproof curtains take the edge off incoming sound, while also improving the acoustics of the room by reducing echo.

I recommend getting larger curtains that run from the ceiling all the way down to the floor. The extra mass between you and the noise will go a long way to reducing the amount of sound that gets in.

However, you should also be prepared to receive reduced lighting from the window, since these curtains are pretty thick.

To see my soundproof curtain recommendations and the best way to install them, check out this article.

3. Install An Additional Window Pane

A secondary window pane placed inside the original window can make a significant soundproofing impact.

This is much cheaper and easier than completely replacing the window – for which you’d have to call an installer, which is not really a DIY project anyway.

You want to be careful about the window pane you select for the new window layer.

My recommendation is getting an acrylic window, and attaching it over the original window.

There are a few significant reasons why acrylic is superior to ordinary glass for this project:

  • acrylic is 17 times stronger than glass (you’ve read that correctly)
  • it allows more light, while also filtering ultraviolet light
  • it’s 20% more more effective at temperature insulation, so you can expect a reduced heating bill
  • it’s easier to handle because it weighs less
  • it’s cheaper
  • it is designed to be an acoustic barrier, despite of lesser density (which makes it weigh less)

The secondary pane should be placed at least 2 inches away from the first, external window.

Make a tight air seal over the existing window and you’re good to go.

4. Make A Window Plug or Barrier

Dense, thick and light, a window plug can act as an acoustic barrier, blocking off sound as well as light.

A typical window plug is made of:

  • a soundproof panel (this is the best one, but there are more affordable options available)
  • a backing board
  • handles

This is one of the bigger projects (compared to the rest on the list), but the results are very rewarding.

But remember, a window plug is only effective if it completely fills up the space within the window frame, so you need to measure everything correctly.

The window plug should occupy at least half the depth of your window seal; a 4 inch window sill, for instance, should be fitted with a plug that is no less than 2 inches thick. A little bit of air gap is necessary so the window plug doesn’t press against the pane.

To ensure that the plug covers every area along the width of the window sill, it should be designed to overlap on the window by no less than 1 inch, allowing the soundproof mat to fit securely into the window sill area.

Add a backing board made of very dense wood material to the plug. However, the chosen board should be relatively light, to aid easy removal. The backing board should exactly match the size of the window sill, meaning the mat sticks out by an inch all around.

You can choose to use an acoustic mat with an adhesive backing, or you could use contact cement to join the mat with the board.

Fitting handles (such as cupboard handles) into the window plug will make it easy to remove. Always keep in mind that these plugs will prevent light from coming in, so you want them to be easily removable.

5. Install Storm Windows

Storm windows add an extra layer of glass that blocks sound quite well. Storm windows can be installed either on the exterior or the interior of the primary window.

Placing it on the interior side is more convenient because it’s easier to install and remove. It also requires less maintenance. Air infiltration is also reduced because it creates a tight seal with the primary window.

As always, better materials provide better results, so you want to carefully select your materials. The best storm windows are made from low e-coating glass. The benefits of e-coating glass are:

  • reduced noise
  • reduced drafts
  • reflects radiant heat 35% better than clear glass storm windows
  • acts as an air sealant, reduces air leakage by 10%

A thicker storm window limits vibrations to a larger degree, and thus, absorbs more external sound.

If you’re a handyman or a handygirl who knows how to use some tools, you can make your own storm window by following this video tutorial.


Those are my top 5 window soundproofing methods.

As I mentioned previously, these methods are not mutually exclusive. In other words, you can do one of these methods or a few of them. It depends on how much noise you’re dealing with and how much you’re willing to invest in your project.

A simple way to start is:

1. seal the gaps and cracks

2. hang soundproof curtains

These two steps are very inexpensive and easy to do, and you will definitely see a change.

If you feel that the noise is still bothering you, then you can expand to the other 3 methods.

I hope this helps! If you have any questions or a piece of advice that you’d like to share with others, you can leave them in the comment section below. – Luka Baron

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