A double glazed window can serve as a sound barrier thanks to the sound insulation and thermal insulation materials.

Many people are concerned about the noise disturbances in their homes. They may want to be able to study, work or simply enjoy a good night's sleep while others converse or listen to television, music or other audio at a high volume through a open window.

Furthermore, noise such as traffic can cause greater lifestyle and health problems.

A double glazed window can serve as a sound barrier thanks to the sound insulation, thermal insulation materials and glass that they are made from. Usually, the two frames of glass of a double glazed window have an inert gas injected in between them. This process, known as sputtering, fills the space between the glass panes with an insulating material that reduces noise transmission through conduction or air flow.

Naturally, through this sound barrier your neighbour's loud music and unwanted noise will be considerably quieter if you have double glazed windows installed in your home. From another perspective, insulation also prevents outside noises from disturbing your sleep at night when neighbours and traffic are typically much less active than during the day.

Consequently, double glazing can substantially improve the quality of life in your own home, with the added bonus of significantly reduced heating costs from a reduction in air flow.

However, double glazed windows and doors do not provide 100% noise reduction and thus will not block outside noise entirely. The most soundproof double glazed windows will reduce noise levels by up to 50%, which is still a significant difference. This means that you can install double glazing without sacrificing your lifestyle or connection with neighbours, while simultaneously enjoying better sleep and more efficient energy usage.

It is highly recommended that homeowners install double glazed windows and doors or replace existing windows if they wish to reduce noise levels and enjoy more peace and quiet within their home environment.

Are double glazed windows soundproof?

The thicker the glass frame is, the better it will insulate noise and help with soundproofing. Double glazing or triple glazing are terms used interchangeably in regards to their effectiveness at more noise reduction. Triple glazing makes slightly better soundproof windows than a double glazed window, with 3 panes of glass instead of 2 panes of glass and having an extra layer of inert gas injected between them. On average, double glazing reduces noise by about 25-50%, depending on how well it has been installed. It is important to ensure that perfect measure is used and that the space between your pane of glass and the sputtering material is tight, as air leakage will negate noise reduction to completely soundproof windows. Noise reduction also depends on the frequency of the sound; low frequencies are more difficult to block than high ones. Newer windows and glass tend to be much better at blocking outside noise and sounds than older ones. While double glazing your windows does not block all sounds and noise like advertised by some companies, it does significantly reduce external noise coming into a home. It may even help with reducing heating bills. Double glazed windows are certainly soundproof enough for most homeowners to live comfortably, with the most recent installation techniques being even better at noise reduction.

What glazing is best for noise reduction?

Triple glazing your window glass does not soundproof better than double glazing or than a single glazed window by a significant enough margin to justify the increased cost.

However, there are a few things you can do to your existing windows in order to increase noise reduction from outside and within your home:

Ensure that all of your window frames properly fitted and is fit for the style of window you have chosen. Aluminium windows and doors should be sealed shut in order to create a sound barrier as wooden ones which absorb more noise. Wood also absorbs more heat making it particularly useful if you live in an area where winter temperatures get low.

Ensure that their aren't any gaps between one pane and another and all frames of glass are tightly sealed. This can be done with acoustic putty or weather-stripping.

If you live in an area where there is a lot of traffic noise, consider replacing your standard windows with windows that are double glazed on the road facing the side of your house (if possible). The noise will be blocked by the mass of the wall and the insulation properties of your home.

Adding insulation to your windows or within your walls can reduce noise from transferring through interior spaces making your house soundproof, but some exterior noises may still manage to leak through. Nevertheless, it is usually more practical than making external modifications like installing new windows (though sometimes this is unavoidable).

Finally, remember that while double glazing does not make your existing windows entirely soundproof by block all exterior noise , it is certainly better than the alternative.

Double glazing is an ideal solution that offers a significant noise reduction where it matters, with the benefit of cost savings.

How much quieter is double glazing?

As the double glazing has two panes of glass with a wider air gap or gas between them, it is far more superior for noise reduction compared to the standard single pane of glass. For soundproofing, double glazing works much better than triple glazing.

Double glazed windows vs U-value

With regards to energy efficiency, there is essentially no difference between double glazing and single glazing your windows because they have almost identical U-values (a measure of thermal conductivity).

Some people may argue that having two panes of glass will reduce heat transfer by 50%, but this only works if the air is trapped behind them - otherwise, it would be like having a single pane of glass. As such, double glazing offers almost exactly the same insulation as standard ones. The New South Wales State Government has an explanation guide to U-values.

Double glazing does help with noise reduction to a significant extent and can even reduce your heating bills (if you live in a noisy area). Triple glazing is not necessarily any better at reducing both sound and heat loss; this would only be true if air was compressed between two layers of glass. It would also make the windows and doors much less transparent.

How to make windows soundproof?

There are a number of things you can do to make soundproof windows and maximize noise reduction. The first thing is to ensure that each air gap between each pane of glass or frame of your window are tightly sealed. This can be done with acoustic putty, weather-stripping or even strips of adhesive moleskin. The second thing is if you live in an area where there is a lot of traffic noise, consider using double glazed windows on the road facing the side of your house (if possible). The noise will be blocked by the mass of the wall and the insulation properties of your home. You could also reduce heat loss from your home by adding insulation to or within your walls as this will make it harder for sounds to enter from outside. Finally, remember that double glazing does not entirely block all exterior noises, but it is certainly better than the alternative.

How many decibels does double glazing block?

How much noise a double glazed window blocks depends on a number of factors including the design, different thicknesses of glass and type of sealant. It is difficult to assess the extent to which a different type of glass or frame will be soundproof as this varies between manufacturers. A better way to gauge how much noise will be blocked by your window is to take sound level readings before and after installation. This can be achieved by buying an SPL meter (sound pressure level meter) which will allow you to test the levels in various rooms throughout your home. Once you've recorded the existing figures it's simply a case of repeating them with your new windows fitted. We should point that professional acoustic consultants often rely on double-glazed windows to reduce noise in the workplace.

What decibel level does double glazing cut out?

Double glazing will vary between different types and manufacturers but most will block at least 30% of outside sound or noise, and up to around 70% in some cases. This is equivalent to approximately 4dB reduction in volume for every doubling of distance (40dB - 20dB). Double glazing can be extremely effective at cutting household running costs as well.

As such a standard single pane window would be roughly equivalent to having an SPL of 45dB inside the room if directly outside your window. The average amplified rock concert can reach around 110db which equates roughly to having a window with 90% light transmission.