Is Glass Soundproof? The Full Facts

Glass is not soundproof, it conducts sound very well which is why single glazed windows do very little to stop noise entering a house.

However, air is a good sound insulator which is why double, or even triple, glazed windows can actually do a very good job of insulating against sound.

There are five key aspects that influence the way glass transmits sound:

  1. Conduction
  2. Resonance
  3. Sound absorption
  4. Isolation
  5. Conduction
is glass soundproof

Resonance

Every glass has some degree of resonance, and one way of dealing with this issue is to use dampeners. 

The more resonance your glass has easier sound will travel through it.

There are specific dampeners designed for fitting the glass material better inside the window frame so that it’s as fixed as possible so that the sound cannot travel throughout it. 

Sound absorption

While glass does absorb sounds, it does so only at its specific resonant frequency (approximately 400Hz). 

This means that any sound waves that are outside of this frequency can either pass through the material and be turned into vibrations -- so you will hear some noise -- or they will be reflected off the material. 

Isolation

Glass is generally a poor choice when it comes to isolation, and that’s why so many people purchase insulated glass windows. 

With those that do not come with this feature, your expectations in terms of noise reduction should have to be minimal. 

Mechanical isolation is typically achieved by adding more layers of the same material, so double or triple glass. 

Air gaps

Air deadens the sound between two or more layers of glass as the vibration of the noise cannot be transmitted as effectively further on. 

Thick glass

As previously mentioned, thicker glass has much better noise-reducing capabilities, and that’s because the vibrations of the sound cannot reach most of its surface. 

Most domestic windows use glass with a thickness of 4mm. 6mm glass will be better, by comparison. 

Acoustic or laminated glass 

Laminating glass with soundproof window film can have a good impact on the amount of sound it allows to pass through, though it certainly isn't going to turn a single glazed window into a soundproof window.

Laminated glass is also a good choice as it usually comes with a high STC (sound transmission class) rating.

Acoustic glass slightly differs from its laminated counterpart, although the effect is much the same. In its case, the space between the two glass layers can be filled with polyvinyl butyral, as well as EVA for ultraviolet radiation protection. 

How To Soundproof Glass

Completely soundproofing a glass window is very difficult to do however there are lots of things that can be done to improve its sound insulation such as:

  • Seal gaps with acoustic caulk - Acoustic caulk reduces sound transmission and also doesn’t interfere with the way you use your windows. You’ll still be able to open and close them properly. 
  • Use Sound-dampening curtains - If you don’t want to deal with too much DIY hassle, installing sound-dampening curtains might be a good solution to your problem if the problem noise is light background noise. 
  • Double-cell shades - As their name suggests, these soundproof(ish) blinds consist of two layers of honeycomb cells, so they do a far better job of dampening sound compared to their single-cell counterparts. 
  • Install window inserts - Soundproof window inserts are particularly good at reducing heavy noise, especially sounds from traffic, trains, ambulance or police car sirens, and others. 
  • Plastic laminates - If adding plastic laminate to your windows doesn’t seem like too much of a challenging task, you might want to know that it’s one of the best ways of soundproofing glass. 

Getting the best type of glass for noise reduction

Whenever you browse the market for new windows, if noise reduction is a concern of yours, there are a number of factors you should focus on. 

How thick are the glass windows? What is their STC rating? How many layers of glass are there and how many can you afford? 

Also, did you know that there are windows that can come with as many as five panes these days? But the higher the number of panes in a window, the more expensive it will be, so do keep everything we’ve mentioned in mind. 

Soundproof glass is more expensive than single-layer glass, and for good reason. Depending on the exact method that was used in soundproofing it, it can block out a variety of noise types, from honking cars to sirens. 

Soundproofing your windows on your own is possible, but you should first see what type you have and what materials you can use with them. 

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Welcome to Soundproof Panda,

I'm Dan, I live very close to an internationally famous stadium which generates an awful lot of noise that I'd rather block out.

This is my place to document what I've learnt on my soundproofing journey.