High performance soundproof secondary windows
Perhaps you’re in the heart of the inner city, trains to the left of you, cars to the right. People trawling the streets beneath you all hours of the day. Or maybe you’re directly under a flight path, suffering the screech of soaring planes from morning to night. Whatever the reason, these high performance soundproof secondary windows are the ultimate solution.
HOW SOUNDPROOF SECONDARY GLAZED WINDOWS WORK?
By placing a soundproof secondary glazing casement window within your existing window frame, these products are designed for those dealing with severe noise pollution. The most robust solution to noise pollution, installing a high performance secondary window delivers up to a 53dB reduction. In conjunction with your pre-existing windows. That means you can expect a reduction of up to 55dB. To put it into perspective, that will turn a jackhammer outside of your home into a quiet whisper in a library.
Noise travels as a pressure wave through the air to reach your ears. By distorting this wave, and dissipating its energy, we can prevent it from ever reaching you. Secondary windows work in combination with your current windows in order to make it as hard as possible for noise to penetrate your home.
It does this by playing with the ‘natural frequency’ of noise pollution. By using acoustic lamineted glass of a certain thicknesses, these windows disrupt the wavelength of the sound, causing it to be distorted and quieten.
TILT & TURN MECHANISM
Featuring a ‘tilt and turn’ system, the internal mechanism allows you to open the window however you like; from the top, bottom left or right. Creating a vacuum-like, not only prevents any draughts or heat loss but reinforces soundproofing.
TIMBER
Constructed with engineered laminated timber, these soundproof secondary glazing units are not only designed to prevent swelling of the frames but also to help dissipate soundwaves.
THE FULL RANGE
SOUNDPROOF
Up to 40dB
Recommended For: Moderate to high noise pollution.
SOUNDPROOF+
Up to 43dB
Recommended For: High levels of noise pollution.
ULTRA
Up to 53dB
Recommended For: High to severe levels of noise pollution.
RECENT INSTALLATIONS
PRODUCT OPTIONS
GLASS
- Specialist noise reduction glass: 40dB, 43dB, 49dB, 51dB, 53dB
- Single glass options: 33.1 (6.4 mm acu), 44.1 (8.4 mm acu), 44.2 (8.8 mm acu), 64.2 (10.8 mm acu), 66.2 (12.8 mm acu)
- Obscure glass
- Safe glass
Bespoke Design
Whether it’s a custom RAL paint finish or tailored design details, all of our windows are bespoke and made to order. You have complete freedom to modify the design to suit your property.
IRONMONGERY
To complete the look, we offer a range of traditional accessories and ironmongery options for you to choose from.

DOWNLOAD THE FULL SPECS
THERMALLY EFFICIENT
It’s not just sound that windows keep out, but the cold too. The glazing has an Ug-value of up to 0.6 W/m²K, meaning that our Secondary Windows are A+ rated.

COMPARE YOUR OPTIONS
REPLACEMENT NOISE REDUCTION GLASS
On the cheap end of the spectrum, the glazing inside your existing window can be replaced with a high performance noise reduction glass. However, modern soundproof glazing can often weigh as much as 4 times your original glazing, causing long-term structural issues.
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SECONDARY GLAZING
A mid-range option, secondary glazing offers significant reductions in noise pollution, however, these windows are considered aesthetically poor due to the fact that they completely steal windowsill space
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SOUNDPROOF CASEMENT WINDOWS
Made to fit, these specialist noise reduction windows are equipped with top of the range noise reduction glass. Designed to specifically deal with noise pollution, these are on the high end of the price range.
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HIGH PERFORMANCE SECONDARY WINDOWS - ULTIMATE NOISE REDUCTION
For truly remarkable reduction in noise, high performance secondary windows are the ultimate solution to all of your noise complaints, providing up to an 55dB reduction. An elegant solution, they will, however, take up considerable space.
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HIGH PERFORMANCE SECONDARY WINDOWS COSTS
The prices displayed below do not include VAT and installation costs.
SMALL SIZE

Price From:
£2,562.00
MEDIUM SIZE

Price From:
£2,979.00
LARGE SIZE

Price From:
£3,792.00
OUR CASE STUDY
49dB Soundproof Ultra Secondary Windows Installation
Welcome to our Bow Quarter Case Study. Join us as we take you on a journey through the assessment, planning, and implementation of our tailored soundproofing solutions, which have brought tranquility and improved quality of life to the residents.
CONTACT US
High performance secondary windows aren’t the solution for everyone, and will often be overkill. If you want to find out more about what will work best for you, speak to one of our soundproof windows advisors, who will be glad to talk you through your options.
HIGH PERFORMANCE SECONDARY WINDOWS FAQs
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What is secondary glazing?
Secondary glazing is when you add another layer of glazing inside of your existing windows to either improve thermal efficiency, or decrease noise intrusion. At the Soundproof Windows we install a whole specialised acoustic window unit inside your existing windows to deliver superior levels of noise reduction. It is the ultimate solution to noise pollution.
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How effective is secondary glazing for noise reduction?
Installing secondary glazing is one of the most successful solutions to noise intrusion. It does this in two ways:
– By creating an air gap between your existing window and the new glazing. Traditionally there needed to be a 100mm gap for optimal performance, however our special seals and glazing design means we only need a 5-10mm gap.
– The secondary glazing also creates another barrier to prevent sound intrusion.
We install specialist secondary soundproof window units designed to tackle your specific noise complaint. In our Ultra range, we can reduce noise by up to 51dB. -
How much does secondary glazing cost?
Our secondary glazing is a premium product and acts more like a secondary window inside of your existing windows. These soundproof secondary windows start from £1,822.00. This is more expensive than standard secondary glazing, but will deliver far greater reductions in noise.
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Can you add secondary glazing to double glazing?
Yes. As long as there is enough room inside of your property. To work optimally, secondary glazing needs to be installed at least 100mm from the existing double glazing. However, our secondary window system only requires 5-10mm of space to perform optimally.
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How thick is secondary glazing?
Secondary glazing ranges from between 8.8mm to 52mm for the glazing alone. The frame is between 68-88mm thick. The glazing that we recommend will depend on the origin and severity of your noise complaint.
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How do you clean secondary glazing?
In order to continue to work optimally, secondary glazing needs to be regularly cleaned, but don’t worry. It’s simple.
– Vacuum or used a soft brush to clear debris between the two windows.
– Use a non-abrasive cloth and diluted washing up liquid (4 parts water to 1 soap) to wash the frames. Wipe dry with a clean cloth after
– Do not use kitchen or bathroom cleaners on the frames.
– Warm water with a small amount of vinegar will clean the acoustic glazing panes and leave them streak-free.
10 YEAR INSURANCE BACKED GUARANTEE
All of our products come with up to a 10 Year Insurance Backed Guarantee provided by the Consumer Protection Association. So you can rest assured that your home is in safe hands.
We have been Trading Standards Approved and are proud to be enrolled on the Buy With Confidence Scheme, ensuring customers just like you have their interests protected.
TRUSTMARK REGISTERED FOR QUALITY
Consumers can feel confident using a TrustMark registered business, as the government-endorsed scheme ensures high quality service and a range of consumer protection options.
AWARD-WINNING PRODUCTS & INSTALLATION
Following awards in 2020, and 2021, The Soundproof Windows was announced as the ‘Best Acoustic Window & Door Installation Company – London’ at the SME News Awards 2022.














