Soundproof Glass – What Is It And How Does It Work?

Is the noise outside driving you crazy? If the answer is yes, the best solution for your problem is soundproof glass. Unlike its normal variant, the soundproof glass is a staple in homes and commercial environments. It’s a boon to anyone who wants peace and quiet at home.

Soundproof glass works by creating a near-impenetrable barrier between the sound and your ears. It takes on the mechanical energy of the sound wave and captures it. Such material can block between 90 to 95% of most sounds, with only a few frequencies as an exception.

Soundproof Glass
Soundproof Glass Panels

If you’re looking to install soundproof glass at home or in your business, it’s important to know how you can take advantage of it. In this guide, we’ll teach you everything you need to know about soundproof glass. This can help you decide if this soundproofing material is worth the cost.

Understanding Important Concepts in Soundproofing

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Before anything, we need to understand that it’s near impossible to soundproof a home 100%. Unless you spend on commercial level materials, there are no residential applications that give total soundproofing. Even then, it’s not very hard to achieve soundproofing of more than 95%.

What we call soundproof does not mean zero sound, but rather a term for 90 – 95% noise reduction. Many soundproof materials block mid-range to upper range frequencies, like a human voice and bird chirps. Low-range frequencies are much harder to block, so you need to take this into account.

To block any noise, you need to fulfill five principles of soundproofing. These are:

  •     Mass
  •     Mechanical isolation
  •     Absorption
  •     Resonance Dampening
  •     Conduction


Mass reduces noise by making it harder for sound to penetrate. As sound is an energy, there’s only so much energy that you can produce to make massive materials vibrate on both sides. The thicker your material is, the less likely sound can penetrate through it.

Mechanical Isolation

With mechanical isolation, it separates the materials from each other, forcing the sound to move through the air. More materials isolated means you lose much of the energy in the air. With no materials to move, the sound will dissipate faster through the air.


Materials with strong absorption capabilities will eliminate a good chunk of the sound wave’s energy. Soft surfaces soak up the energy of the sound. Instead of reflecting it, it dissipates it across its surface, making it weaker in the process.

Resonance Dampening

With resonance dampening, your material reduces the magnitude of the sound. Most dampeners convert the mechanical energy into something else, whether it’s into heat or something else.


The last principle of soundproofing is conduction, where there is a transference of energy from a material to another. By reducing conduction through dampening materials, you can help dissipate as sound travels.

Soundproofing Windows

Before I go into details about soundproof glass, Check out my article on soundproofing windows and don’t miss out the video.

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How Does Soundproof Glass Work?

So, now that we know how soundproofing works, how does soundproof glass work? Many homes use barriers that take on noise and try to reflect it to the outside. Much of these barriers include walls, drywall, windows, and doors. They block direct sound waves that come from the outside.

The glass itself is a bad soundproofing material. It immediately vibrates once it receives sound waves, which it either reverberates or lets through. To make glass soundproof, a couple of steps happen.

First, soundproof glass manufacturers will add mass, making the glass thicker. As we know, thicker materials allow less sound to pass through. Thick glass lets the energy dissipate on its surface, reducing noise.

When going for thickness, any sheet of glass will have what we call coincidence frequency. Coincidence frequency is a phenomenon where, due to shape and size, glass can amplify sounds instead of dampening it. When this happens, you get louder noise instead of eliminating it.

The usual problem with thickness comes with lowering the frequency where the glass panel vibrates. With enough thickness, the frequency of the audio can go so low that it can be at an audible range to the human ear.

To prevent coincidence frequency, a lot of soundproof windows use a variant thickness for multiple layers. The usual combination is around a 30% differential in thickness, which allows for a better decoupling interlayer.

Related article: Soundproofing sliding glass doors.

Using Plastic Laminates For Soundproofing

The second process is to add laminate on the glass. Plastic laminate and other composites reduce the vibrations in the glass. It reduces noise transmission and makes the glass more rigid than its usual structure.

In some soundproofing glasses, they use a plastic interlayer that sandwiches a layer of plastic in between two glasses. The glass-plastic-glass layer makes the window much firmer, reducing the vibrations that the material transmits. This setup has the secondary advantage of making the soundproof window much more durable.

This plastic layer can use different systems, including:

  •     Polyvinyl butyral (PVB)
  •     Micro-rubber spacers
  •     Vacuum spacing

PVB is a resin that allows for superior binding while keeping good flexibility. It is also a superb sound dampener, able to prevent sounds at a frequency range of 1000 – 3000 Mhz. This range is the most sensitive range for human ears. By eliminating vibrations from this, PVB can reduce noise by as much as 10 dB, which is a good 50% noise reduction.

Micro-rubber spaces help create a barrier between the window and the sill, cutting down the noise from the frame itself. Vacuum spacing is a whole other function.

Using Multi-Pane Technology

Some soundproofing glass functions work through the use of panes. By adding a vacuum space in between two panes of glass, you prevent sound from coming in. By using double pane windows with a full vacuum in between, the sound stops on the first layer. The bigger the gap that you create, the better the mechanical isolation you get.

For some types of soundproofing windows, some add a secondary window inside and an existing window outside. The isolation brought about by the thick air space traps the sound. The noise reflects outside, preventing a majority of it coming in.

Thicknesses and glazing use will depend on the needs of the user. Many soundproof glass installations are custom work, as every household has a different need. This can change depending on the source of the sound and level of noise reduction needed.

Finding Superior Soundproof Glass

So, what’s the best way you can do to find good soundproof glass? There are a few factors that you need to consider when choosing soundproofing glass. These include:

  •     Thickness and STC Rating
  •     Number of panes
  •     Cost
  •     Extra benefits

As you can see, the criteria for choosing the windows are short and sweet. You want to keep these details in mind when choosing your next soundproof glass.

Consider Thickness and STC Rating

As we know, the thickness of your windows is a crucial part of soundproofing. It’s the one that absorbs and dampens the vibrations you get from the source of the noise. When picking your soundproof glass, the thickness is important.

The thicker the glass that you use, the better it can cut down on the noise. To know how much noise your soundproof glass can reduce, you want to look at its STC rating. Sound transmission class rating, known as STC rating, is a crucial part of soundproofing.

STC rating is a numerical integer that classifies how well a material can muffle and dissipate sound energy. It is the scale used to measure the soundproofing ability of many materials. These materials include walls, floors, doors, and windows.

With soundproofing, the higher the STC rating, the better the soundproofing becomes. At STC 25 and below, you can hear a basic conversation from the outside. To give you a perspective on how STC rating for materials work, normal steel or timber has an STC rating of 13.

A change in STC rating, much like noise, is logarithmic. A change of ±1 in STC is almost imperceptible. A change of ±3 is barely there, but you will notice a change. An STC change of ±5 is noticeable, while a change in ±10 represents a 50% reduction in sound transmission.

Once you get to STC 30, loud speech is audible, but normal conversations are not. By the rating of 35, loud speech becomes unintelligible.  To get full soundproofing that muzzles almost all noises, you need a compound of materials with an STC rating of 60.

Most soundproof glasses have an STC rating of somewhere between 20 to 38, depending on the system. If you’re looking to cut down on a majority of the noise, this should be more than enough. If you want higher soundproofing, you want to support your soundproofing glass with something else.

Consider the Number of Panes

panes of soundproof glass
More panes improves soundproofing quality of glass

Another crucial consideration with soundproof glass is the number of panes. As we know, space between two layers of glass can help trap the noise and dissipate its energy. Does that mean that the more panes you have, the better soundproofing you get? Yes and no.

You need to know that the more panes you add, the more expensive your window becomes. Even if soundproofing is that important to you, the benefits that you get from adding more panes beyond two will give you diminishing returns.

Some studies show that adding a third pane to your soundproof glass only gives you a dollar extra in savings per year.

With double pane windows, you’re getting two soundproof glasses of differing thicknesses. You will then have either a plastic laminate or a gas layer separator inside. Both offer different benefits, so you would need to pick what you need.

If you’re looking for pure soundproofing, you want to stay with a laminate. It won’t give you a lot of efficiencies and reduced heat loss, but it can block more noise. If you’re looking for total benefits, you want a soundproof double pane glass with low-E coating.

Consider The Extra Benefits Of Soundproof Glass

At the end of the day, depending on your purpose, your goal with your glass does not stop with soundproofing. With that said, you would want to have soundproofing glass that can do other things. Not only can you get peace of mind, but you also get more out of it. Consider what other benefits the soundproof glass can give you.

Some glass manufacturers add extra layers of laminate on the glass. Special laminates like Low-E coating help with keeping temperatures stable indoors. They prevent excess heat and cold from penetrating, which helps regulate indoor temperature.

Some glasses also have anti-radiation coating that helps with UVA and UVB sun protection. Doing so helps not only with your health but also reduces furniture bleaching in your home.

Consider The Cost

So, is soundproof glass worth the cost? This depends on the uses that you have and the goals you set for each of them. The cost of soundproof glass and windows can change with a few different factors. These include:

  •     Window style
  •     Type of glass treatment
  •     Size of the glass and frames
  •     Amount of windows
  •     Type of application

Soundproofing can be expensive to do if you go out there without a goal. Make sure you have a goal first, as not all people need to muzzle all the noise they encounter.

For example, if you live in a suburb, you won’t need to get a total sound reduction. Clearing mid-range and high frequencies should be more than enough to handle most of your needs. The usual household only needs an STC rating somewhere around 30 – 40 to be useful.

If you’re the type who likes to play instruments or live near airports, you’ll likely want superior soundproofing. This can be expensive for you, but you don’t have to settle with soundproof glass.

The smartest way to soundproof your home is to use materials that can support your soundproofing glass. For example, you can use heavy curtains to improve the soundproofing capability of your glass. There are also ways to reinforce your walls with both drywall and insulation that can reduce noise from the outside.


Soundproof glass is wonderful material and a great way to cut much of the noise that comes from the outside. Two pieces of special glass and some other treatments give your glass superior noise reduction. If you’re soundproofing your home, this glass is a vital material that can help.

Even then, remember that your soundproofing is only as good as your weakest material. It doesn’t matter if you have the most expensive soundproof glass in the world. If your other materials are not up to the task, then the entire system is useless. Have your materials support each other to cut down the noise.

Are you considering soundproof glass for your needs? See how it functions first to know if it’s right for you.

Also read: 6 Ways To Soundproof Windows In An NYC Apartment

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