How much noise reduction can I expect from adding secondary glazing - body iamge 1


If you’re trying to find the best way to reduce noise in your home and keep all of those outside noises, outside, then secondary glazing might be something you’re interested in. Your windows play a vital part in keeping your home both quiet and warm, and it’s important that you’re keeping them up to date if you want peace and comfort while you’re home.

But if you’re going to invest in secondary glazing for the sake of noise reduction, are you actually going to get your money’s worth? The simple answer is yes. Secondary glazing can reduce the noise from outside by up to around 40%-80% (results depend on various factors)- which is a significant difference. If you’re struggling to get sleep because of noisy streets, or you just can’t enjoy the peace and quiet at home, then secondary glazing is an absolute must.

However, it’s not as simple as just having secondary glazing installed, there are different types of glass and fittings that need to be considered, and the best for you is going to differ based on your preferences and what your home can accommodate – it’s not just a one-size fits all deal. So what can you do to improve how well your secondary glazing reduces noise pollution?

Understanding what’s important

When it comes to getting the most out of your secondary glazing, it’s important that you understand what factors are important when having it fitted. It’s not just the glass itself that does all of the work, it’s the thickness of the glass, the spacing between the glazing, and even the frame it’s installed in. A cheap frame can let noise in just as much as a single-glazed window, so it’s important that you consider everything before you go looking for a secondary glazing company.

The glass

First of all, an important factor to consider is the glass that you plan on having installed for your secondary glazing. You don’t want something of just any thickness, as it’s not always going to be effective for keeping the sound out. Typically, you’ll want the standard single-glazed 6.4mm acoustic laminate glass for your secondary glazing. It can help to reduce the noise outside significantly, and it’s perfect for those living in areas with a lot of noise. Generally, most houses won’t need more than this, and it should work for keeping everyday noises out of your home – or at least keeping them quiet while you’re inside.

With that said, some need a much heavier noise reduction, and the standard single-glazed option isn’t always going to be the best. While it would be unnecessary in most situations, there’s also a 16.8mm acoustic laminate glass that can help to keep the louder and more severe noises quiet. It’s more expensive, but situations with a severe amount of noise pollution will require something of that thickness if you’re hoping to keep the property quiet.

The gap between

More important than the glass itself is the way your secondary glazing is installed. While it takes up more space in your home, it’s important to consider having a larger gap between the external window and the secondary glazing you have installed. Technically speaking, the larger the gap you can have between the layers of glass, the better. A smaller gap will have a more difficult time reducing that outside noise coming in.

Having a gap of at least 100mm can really help to keep the noise out, but if you’re having a lot of trouble with the current noise pollution, you’ll want to consider a longer distance – all the way up to 200mm. It’s not always necessary to have a gap so big between your glazing’s, but when there’s a lot of noise outside on a daily basis and you need that peace and quiet, it’s worth consideration. Of course, not every window can be fitted with such a large gap, but it’s important to understand that the larger gap you can have, the better results you’ll observe once it’s in use.

Your frame

While it’s not completely relevant to your window glazing, your frame is something you should absolutely take into account when trying to keep the noise out. A cheap or damaged frame is going to have cracks and air holes in it – which is going to severely impact how effective your noise reduction is. If you’re going to upgrade your glazing, you should make sure your external window frame also isn’t in need of replacement. Minor cases won’t need a complete replacement, but it’s important that it’s treated and repaired to ensure good results after your installation.

How it actually works

So we know that having secondary glazing can reduce the noise pollution in your home by up to 40%-80% and that having a greater gap between the glass can play a significant role in that, but why? For you to understand why secondary glazing can help soundproof your home, you need to understand how sound works, and how it’s effectively stopped in its tracks.

The sound itself, while not visible, travels in waves. These waves project and bounce around different surfaces while passing through others – which is why you can hear noises despite them being outside. However, these noises become distorted when intercepted, making them harder to hear clearly – effectively making them much quieter. While your current windows will likely be reducing the noise somewhat, they’re not completely effective in distorting these sound waves – which is where the secondary glazing comes in. Acoustic laminated glass is specially designed to keep louder noises out and disrupt even the louder sound waves.

So when there are a lot of cars driving by your home, or your neighbours are being noisy, you’re hearing them because sound waves are penetrating your home. Regular glass isn’t the best way to intercept these waves, which is why secondary glazing using acoustic laminate is very effective.

Secondary glazing vs double glazing

If you’ve never really looked into it, you might not be aware that there’s a difference between secondary glazing and double glazing. If you’re going to soundproof your home effectively, it’s important to know that they are completely different – and double glazing isn’t going to be anywhere near as effective as secondary glazing.

The purpose of double glazing is to insulate your home better than single glazing, but it’s technically just one window – with two panes. Between the two panes is a gas which helps them to provide better insulation to your home. These windows are also stronger and more secure, which is great for security.

Secondary glazing isn’t just having one single window within the window frame, as you’re effectively having another window installed close to your already existing window. This does nothing to improve the strength of your windows, however, it’s great for soundproofing your home. The larger gap between the panes is what helps to distort and dissipate soundwaves, which is where the main difference between double glazing and secondary glazing comes in.

Reasons to install

Noise pollution comes in many different forms, and everyone has their own personal experiences that lead them to get their secondary glazing installed. If you’re having trouble justifying the investment, here are some of the more common reasons secondary glazing is installed:

Loud traffic

Living on a busy road can often make it difficult to relax at home. There are constant noises of cars driving by, and if there’s a lot of traffic all throughout the day, you’re not going to get much quiet until the evening. Sometimes you may even be woken in the night, which is where secondary glazing can really help.

Noisy neighbours

We can’t help who moves in next door, and lifestyles will clash from time to time, making your home experience a nightmare if you don’t enjoy the noise your neighbours are putting out. Getting peace and quiet when the people living next to you are the ones disrupting it can feel impossible. Reducing noise pollution in your home to avoid this can make your home much more tranquil and reduce tension between you and your neighbours.


While construction projects are usually temporary, some can go on for long periods of time if you’re unlucky enough to live near an ongoing one. A lot of the time these construction projects start very early in the morning and continue until the evening, so if you’re trying to sleep in or work from home – it can be impossible to avoid the noise. No one wants to have to deal with loud construction noises, it can be distressing when you’re trying to relax or focus. Having secondary glazing installed can solve the issue within an afternoon, and you can avoid months of upcoming stress.

If you’re looking to reduce noise in your home, having secondary glazing installed is an absolute must. Your windows are the most vulnerable part of your home for sound penetration, and having that secondary glazing can help to reduce the noise levels.