Services - Acoustic Glass, Glazing, Units, Double & Secondary Glazing for Noise Reduction & Soundproof Windows
We provide a complete range of services for the noise reduction and soundproofing of windows:
- acoustic glass
- acoustic glazing
- acoustic sealed units
- acoustic double glazing
- acoustic secondary glazing
The table at the end of this page provides a guide to noise reduction for each application.
About - Acoustic Noise Reduction & Soundproofing for Windows
Acoustic noise reduction for windows can be a complicated subject - if you would prefer to have a chat with someone, please feel free to give us a call.
We have seen a lot of overly technical, misleading, and frankly downright incorrect information on this subject.
Our aim is to give you the relevant information in understandable, layman’s terms - so that you can make an informed decision about your requirements.
Our chart at the foot of the page lists all of the options for soundproofing - and tells you the amount of noise reduction that each will achieve.
If you would like a deeper understanding and more detailed information about noise - how it is measured - and how to reduce it, then we can thoroughly recommend this guide from our supplier of Stadip Silence ® Acoustic Laminated Glass:
Stadip Silence ® Acoustic Laminated Glass Stadip_Silence_Brochure Download
Acoustic Laminated Soundproof Glass
The best noise reduction through glazing is obtained by using an acoustic laminated glass.
This type of glass is actually a “sandwich” of two sheets of glass bonded together and incorporating a special PVB (Poly Vinyl Butyral) interlayer.
Acoustic glass reduces noise transmission by a combination of:
- Reflecting the noise away from the glass
- and
- Absorbing the noise within the PVB interlayer
We stock and cut to size 6.4mm acoustic laminated glass for delivery to you. 6.4mm is the most commonly used acoustic glass and dependant upon sizes and quantity, is normally available for same day collection or delivery within 1 to 3 days.
For thicker soundproofing glass, please contact us for a delivery date, quoting the glass thickness and sizes:
- 6.8mm
- 8.4mm
- 8.8mm
- 10.4mm
- 10.8mm
- 12.4mm
- 12.8mm
- 14.8mm
- 16.8mm
- 20.4mm
- 25.5mm
Acoustic Glazing
We are fully experienced in acoustic glazing and offer a professional on site or in-house service for the following:
- Putty glazing and re-glazing
- Bead glazing and re-glazing
- Patent glazing and re-glazing
- Metal, PVC, timber & aluminium windows - glazing and re-glazing
We carry out all the above on site.
As well as working with single glazing, we also supply and install:
For commercial customers, we provide acoustic glazing services to a wide range of clients, including:
- Offices
- Recording studios
- Gyms
- Dance studios
- Clubs & pubs
- Hotels
- Restaurants
Acoustic Glass Units
We manufacture to order all thicknesses and sizes of sealed, acoustic glass units.
For the best noise reduction with an acoustic sealed unit:
- One glass should be about half as thick again as the other - this reduces the risk of sympathetic resonance (vibration) and maximises the soundproofing across the greatest range of noise frequencies
- The bigger the gap between the two panes of glass, the better
- Gas filled glazing units are more effective than air filled units
Words of caution regarding the replacement of units for noise in residential windows:
- In most cases a 6.4mm acoustic laminated glass - 6mm up to 18mm gap - 4mm float or Low E glass sealed unit will do the job and will be within the load ratings for the hinges.
- If you are considering using thicker glasses - then you need to identify whether the hinges will support the additional weight.
- Failure to do so could lead to opening lights beginning to drop over time and difficulty closing the windows and engaging the locks.
A note about triple glazed units for noise reduction:
- If the 3 panes of glass are all the same thickness noise reduction will not be noticeably improved and low frequency sound will be more likely to cause resonance and vibration.
- Testing has not shown any significant improvement over 2 panes and the costs massively outweigh any benefits.
Acoustic Double Glazing
We supply and fit new replacement windows with acoustic double glazed sealed units.
If your windows need replacing and you are having noise problems, then this may be the best all round solution for you.
Having said that, we do get called upon to install secondary glazing over existing sealed unit type replacement double glazing - because of continuing noise problems.
Usually, these are older replacement windows, with non-acoustic sealed units - but the fact remains that in general, for noise reduction and soundproofing, secondary glazing will provide the maximum sound insulation.
If your windows do not actually need to be replaced, then you can also consider:
- If single glazed, replacing the existing glass with single glazed acoustic glass
- If double glazed, replacing the existing sealed units with acoustic sealed units
- Installing secondary glazing
You can see the noise reduction for each option in the table below.
We do not replace single glazing in wooden windows with sealed units, because:
- Fitting sealed units will reduce the depth of the original frames & severely weaken the joints
- Sealed units will typically weigh between 2 & 3 times the weight of the original single glass and this will strain the joints and overload hinges, handles & locks
If the windows were not originally designed to take sealed units, then trying to fit them will at best considerably shorten their life and at worst cause breakages during the process.
We supply and fit the following types of double glazed replacement windows:
- PVC hinged casements
- PVC sliding sash windows
- Aluminium hinged casements
We have been a FENSA registered installer since the beginning of the registration requirement in 2002:
- FENSA registered number: 32788
Acoustic Secondary Glazing
The most effective treatment for reducing noise entering through the windows is secondary glazing.
This is because:
- The gap between the 2 panes of glass plays a crucial part in effective Noise Reduction
- For 4mm Glass, each increase in the gap of 25mm (1 inch) approximates to an increase in Noise Insulation of 0.75dB Rw
- For 6mm Glass, each increase in the gap of 25mm (1 inch) approximates to an increase in Noise Insulation of 1.25dB Rw
To put that into perspective, each 10dB decrease in sound intensity achieves a halving of the noise that passes through the window.
Unlike sealed units, which generally have a maximum gap of 20mm (approx. ¾ of an inch,) secondary glazing can take full advantage of the depth of your window reveal:
- To maximise the noise reduction
We have listed the sound insulation values of all the different options on this page in the table below, so that you should be able to decide what is the right solution for you.
If you would like to talk it through, please give us a call. Alternatively, if you are not sure and would like an on-site evaluation, one of us can pop out and do that.
All Types Of Noise Can Be Dealt With




Every situation where there is a noise problem is unique. It depends upon the specific individual mix of:
- Types of noise
- Mix of high & low sound frequencies
- Direction/s from which the noise is coming
- Each person’s individual sensitivity to noise
To deal with these variances, the basic noise measurement - dB - is measured and expressed as follows:
- An electronic filter that approximates the average frequency response of the human ear is applied - this is called - A-Weighting - & is scientifically expressed as - [dB(A)] - however it is common practice that the A-weighting is referred to simply as - dB
- Different frequencies & volumes of noise react in different ways, again this has to be averaged out & in this case it is expressed as the - Weighted Reduction - expressed as - dB Rw
- dB Rw is always expressed as the - Combined Noise Reduction - of the Complete Glazing System - whether that be a single pane of glass, a sealed unit or an original single pane + secondary glazing
The noise reduction table strictly follows the above standards, so that all measurements are - dB Rw:
- Standard 4mm single glazing achieves a 29 dB Rw noise reduction over just having a hole in the wall
- Each - 10 dB Rw - of noise reduction achieved by the new glazing system - reduces the noise that you hear by 50%
Noise Reduction Table
WINDOW TREATMENTS RE-GLAZE - NEW UNITS - REPLACE - SECONDARY GLAZE | STARTING NOISE REDUCTION | NEW NOISE REDUCTION | NOISE REDUCTION GAIN | % LESS NOISE YOU HEAR |
---|---|---|---|---|
Single Glazed Window - 4mm Glass Hack Out Glass & re-glaze with: Single Glazed - 6.4mm Acoustic Glass |
29 dB Rw | 35 dB Rw | 6 dB Rw | 30% |
Existing Sealed Unit - 4mm / 6 - 16mm Gap / 4mm Glass Remove & replace with: New Sealed Unit - 4mm / 6 - 16mm Argon / 6.4mm Acoustic |
30 dB Rw | 37 dB Rw | 7 dB Rw | 35% |
Existing Sealed Unit - 4mm / 6 - 16mm / 4mm Glass Retain & add: Secondary Glazing - 100 Cavity - 6.4mm Acoustic Glass |
30 dB Rw | 43 dB Rw | 13 dB Rw | 65% |
Single Glazed Window - 4mm Glass Remove & replace with: New Replacement Windows - 4mm / 16mm Argon / 6.4mm Acoustic |
29 dB Rw | 38 dB Rw | 9 dB Rw | 45% |
Single Glazed Window - 4mm Glass Retain & add: |
29 dB Rw | |||
Secondary Glazing with a 50mm Reveal / Cavity & 4mm Glass | 34 dB Rw | 5 dB Rw | 25% | |
Secondary Glazing with a 50mm Reveal / Cavity & 6mm Glass | 36 dB Rw | 7 dB Rw | 35% | |
Secondary Glazing with a 50mm Reveal / Cavity & 6.4mm Acoustic | 40 dB Rw | 11 dB Rw | 55% | |
Secondary Glazing with a 75mm Reveal / Cavity & 4mm Glass | 35 dB Rw | 6 dB Rw | 30% | |
Secondary Glazing with a 75mm Reveal / Cavity & 6mm Glass | 37 dB Rw | 8 dB Rw | 40% | |
Secondary Glazing with a 75mm Reveal / Cavity & 6.4mm Acoustic | 41 dB Rw | 12 dB Rw | 60% | |
Secondary Glazing with a 100mm Reveal / Cavity & 4mm Glass | 36 dB Rw | 7 dB Rw | 35% | |
Secondary Glazing with a 100mm Reveal / Cavity & 6mm Glass | 38 dB Rw | 9 dB Rw | 45% | |
Secondary Glazing with a 100mm Reveal / Cavity & 6.4mm Acoustic | 42 dB Rw | 13 dB Rw | 65% | |
Secondary Glazing with a 125mm Reveal / Cavity & 4mm Glass | 37 dB Rw | 8 dB Rw | 40% | |
Secondary Glazing with a 125mm Reveal / Cavity & 6mm Glass | 39 dB Rw | 10 dB Rw | 50% | |
Secondary Glazing with a 125mm Reveal / Cavity & 6.4mm Acoustic | 43 dB Rw | 14 dB Rw | 70% | |
Secondary Glazing with a 150mm Reveal / Cavity & 4mm Glass | 38 dB Rw | 9 dB Rw | 45% | |
Secondary Glazing with a 150mm Reveal / Cavity & 6mm Glass | 40 dB Rw | 11 dB Rw | 55% | |
Secondary Glazing with a 150mm Reveal / Cavity & 6.4mm Acoustic | 44 dB Rw | 15 dB Rw | 75% | |
Secondary Glazing with a 175mm Reveal / Cavity & 4mm Glass | 39 dB Rw | 10 dB Rw | 50% | |
Secondary Glazing with a 175mm Reveal / Cavity & 6mm Glass | 41 dB Rw | 12 dB Rw | 60% | |
Secondary Glazing with a 175mm Reveal / Cavity & 6.4mm Acoustic | 45 dB Rw | 16 dB Rw | 80% | |
Secondary Glazing with a 200mm Reveal / Cavity & 4mm Glass | 40 dB Rw | 11 dB Rw | 55% | |
Secondary Glazing with a 200mm Reveal / Cavity & 6mm Glass | 42 dB Rw | 13 dB Rw | 65% | |
Secondary Glazing with a 200mm Reveal / Cavity & 6.4mm Acoustic | 46 dB Rw | 17 dB Rw | 85% |
Visit our Contact Page for Opening Hours , Address & Email
Name & Registered Address: 36 Byron Road, Harrow, Middlesex, HA3 7ST. Registered in England and Wales - Registered Company No. 13360440 :
Registered Office: 30 Milton Road, Westcliff-On-Sea, England SSO 7JX VAT Registration No. 389 2452 57
Privacy Notice : Privacy & Electronic Communications : Terms & Conditions
© 2022 North London Secondary Glazing - All rights reserved.