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If you’re a homeowner struggling with noise as a result of living near a busy road, a train station or an airport, double glazing is the best solution. As well as a quieter home, you’ll find that life is more healthy because you’ll be able to get a better night’s sleep, and your living space will feel calmer. It’s important to note however that double glazing isn’t entirely soundproof, but it will reduce noise considerably.

We hear noise through single-glazed windows because when sound hits the pane, it vibrates, causing the air on the other side of the window (inside) to vibrate, which passes to our ears in sound waves.

Reducing noise with double glazing

If you add an extra layer of protection to your glass through double glazing, these vibrations are greatly minimised, making your home a much quieter place to live. When double glazing is fitted correctly, you’ll find there aren’t any cracks or gaps around the window, which also helps to reduce noise. When sound hits a double-glazed pane that is properly sealed, the vibrations have no way to get through.

Argon gas that is located between the two panes of glass also has different properties in the way it handles sound waves (as opposed to normal air), reducing the sound waves and dampening them. This guide will talk you through how double glazing can help with noise reduction.

How much does double glazing reduce noise?

Noise pollution can be a real pain for homeowners when they want to relax and achieve peace and quiet in their homes. In cities and busy areas, traffic and road noise is one of the biggest problems. Cars, public transport vehicles, and people walking past the property can have a significant impact on well-being and sleep.

If you live near train tracks, passing trains can also be an issue, and cause lots of disturbance at all times of the day and night. Single-glazed windows are particularly prone to letting such noise into a building. This can be a real problem for people living in congested areas or on flight paths. If your windows are old or single-glazed, you may want to consider getting double-glazing to make your home more peaceful.

35 decibels of noise is considered acceptable. If you live in a busy or built-up area with traffic and congestion, this number can increase to around 70 decibels. People living near airports or on flight paths may find themselves having to deal with noise pollution that is 100 decibels or even more.

Having double glazing can reduce noise by around 30-35 decibels, although this will depend on the quality and structure of the double-glazing units used, as they vary in quality depending on the manufacturer/installer.

Single glazing vs double glazing noise reduction

Single glazing has a typical sound reduction index of 25 decibels, which is the amount by which it can reduce general noise pollution. By contrast, double glazing can reduce noise pollution by 30 to 35 decibels, making it much more effective at tackling noise pollution.

The amount of noise that is reduced by double glazing does however depend on factors such as glass thickness, the frame the window is placed in, and the general design of the windows.

Good quality double glazing undergoes rigorous testing to ensure that it keeps out noise of around 30 to 35 decibels. Our Comfort glass can provide 20% better noise reduction compared to standard double-glazed windows.

Single vs double glazing noise reduction


Typical sounds and decibel levels

As a guide, a person can hear sounds of up to 140 decibels. Between 0-30 decibels is considered quiet, and the average home noise is around 40 decibels. Anything over 85 decibels is considered damaging to hearing, depending on how long you’re exposed ot the noise.

Double glazing can help to reduce noise that is over 30 decibels because the gas between the two panes of glass helps to absorb sound vibrations, which can reduce general noise by up to 65%. If you have uPVC framing, this can help to lower sound vibrations even more.

DecibelsLevel of sound
0-20dbQuiet – Rustling leaves
20-50dbSoft – Whispering or quiet talking
50-70dbModerate – Normal talking
70-90dbLoud – Vacuum cleaner
90-120dbVery loud – Concert music
120-130dbUncomfortable – Plane taking off
130-140dbDangerous – Fireworks

Source [1]

Qualities of double glazing that reduce noise

One of the main reasons that double glazing is so good at reducing noise is because of its thickness. Double glazing consists of two panes of glass, with an air or argon gas cavity in between them. The thickness of the glass limits noise from travelling through them, and the cavity between the panes helps to dampen noise vibrations.

Having two panes rather than one creates an extra layer of protection against sound from outside the building. Many people opt for uPVC frames alongside double-glazed windows, as this is better at reducing noise than aluminium frames.

The average gap between double-glazing panes

The gap between the two panes of glass in double glazing is very important. The optimal size for this gap is between 14-16mm. If the gap is less than 14mm, it can increase heat transfer. If the gap is greater than 16mm, it can create convection.

Does triple glazing reduce noise more than double glazing?

In short, triple glazing provides even more protection from noise pollution than double glazing. Triple-glazed windows have three panes of glass instead of two, with gas or air-filled cavities between them, which helps to block out sound even more effectively. Compared to double glazing, triple glazing has a greater sound reduction index (SRI).

The number of decibels it can reduce noise pollution by depends on factors such as glass thickness, spacing between the panes of glass, air or gas used in cavities, and the window design. Aside from combating noise pollution, triple glazing is often installed because it can keep a home warmer, and lower energy bills.

Three panes of glass also provide more protection against break-ins. Triple glazing is, however, more of a financial outlay than double glazing, so it’s always worth considering how much noise you need to block out, and whether triple glazing is worth it financially. Sometimes, double glazing can be enough.

Best double glazing for noise reduction

As a result of building regulations, double glazing has become a requirement for all new replacement glazing since 2002. Homebrite’s double glazing is available in toughened Planitherm Comfort and Comfort Plus glass provided by Saint-Gobain – a world leader in the provision of building materials.

Our double glazing offers an ‘A’ window energy rating, and we have one of the biggest selections of aluminium, timber-look, and uPVC windows and doors to choose from.


[1] Decibel Chart of Common Sounds – Decibel Pro –  https://decibelpro.app/blog/decibel-chart-of-common-sound-sources/