Acoustic Glass: A Complete Guide to Noise-Reducing Windows
9th September
If outside noise is making it difficult to relax, sleep or enjoy your home, upgrading your windows could make a noticeable difference.
Acoustic glass, sometimes called acoustic glazing or noise-reducing glass, is specifically designed to reduce the amount of external sound passing through your windows. It can be particularly useful for homes close to busy roads, railway lines, airports and other sources of persistent external noise.
But how does acoustic glass work, and is it actually worth paying more for?
In this guide, we explain everything you need to know about acoustic glazing, including how it compares with standard double glazing and triple glazing, who could benefit from it, and what you should consider before choosing it.
What is acoustic glass?
Acoustic glass is glazing that has been specifically engineered to improve the reduction of external noise entering your home.
Unlike standard double glazing, where the two panes of glass are typically the same thickness, acoustic glazing can use different glass thicknesses and laminated acoustic glass to disrupt sound waves more effectively.
For example, the acoustic specification supplied by our manufacturer uses a 6.8mm laminated acoustic pane alongside a 4mm pane, with an 18mm cavity.
The different thicknesses help prevent sound energy from passing through the glass as easily, while the laminated construction provides an additional barrier to sound.
The result is a window that can provide substantially better sound reduction than standard double glazing.
How does acoustic glazing work?
There isn't one single feature that makes a window acoustic. Instead, its sound-reduction performance comes from the way the complete glazing unit is designed.
Three important factors include:
1. Different glass thicknesses
Using panes of different thicknesses helps disrupt sound waves and reduces the likelihood of resonance occurring between the panes.
This is one of the key differences between acoustic glazing and a conventional double-glazed unit.
2. Laminated acoustic glass
Acoustic glazing commonly uses laminated glass specifically designed to improve sound reduction.
The laminated construction helps absorb and reduce sound energy passing through the glass.
3. The sealed glazing unit and window installation
The glass isn't the only consideration.
The cavity within the sealed glass unit, the quality of the window seals and the installation itself all contribute to the overall performance of the finished window.
This is why it is important to consider the complete window and glazing specification, rather than simply looking at the thickness of one pane of glass.
How much noise can acoustic glass reduce?
The exact performance of a window depends on its specification, size, frame and installation, but the manufacturer data supplied to us gives a useful comparison.
For the glass units themselves, the tested sound reduction figures are:
Glazing |
Sound reduction |
Standard 4-20-4 double glazing |
31 dB |
6.8-18-4 acoustic double glazing |
36 dB |
4-12-4-12-4 triple glazing |
32 dB |
These figures are for the glass unit only, rather than the complete installed window.
This is an important distinction when comparing products. The acoustic double-glazed specification achieves a higher sound-reduction figure than the standard triple-glazed specification supplied by the manufacturer.
In other words, adding a third pane of glass doesn't automatically make a window better at reducing noise.
Is acoustic double glazing better than triple glazing for noise?
If your main reason for replacing your windows is noise reduction, acoustic glazing can be a more appropriate choice than simply upgrading from double to triple glazing.
Triple glazing is primarily designed to improve thermal insulation. Adding a third pane can improve energy efficiency considerably, but it doesn't necessarily provide a significant improvement in sound reduction.
In the manufacturer's comparison, the standard triple-glazed unit achieved 32 dB compared with 31 dB for standard double glazing, while the acoustic double-glazed unit achieved 36 dB.
That demonstrates an important point:
More panes of glass doesn't necessarily mean less noise. The glazing specification matters.
If your priority is keeping your home warmer and maximising thermal efficiency, triple glazing can be an excellent option.
If your priority is reducing traffic or other external noise, acoustic glazing is specifically designed for that purpose.
Acoustic glass vs double glazing
Standard modern double glazing already provides a degree of sound reduction.
A typical 4-20-4 double-glazed unit in the manufacturer's information achieves 31 dB sound reduction.
That's perfectly suitable for many homes, particularly where external noise isn't a major problem.
Acoustic double glazing takes this further by using a specialist laminated acoustic pane and different glass thicknesses. The supplied acoustic specification achieves 36 dB.
So, if you're replacing your windows because you're fed up with hearing traffic outside, upgrading from standard double glazing to acoustic glazing could be a more targeted solution than simply choosing a conventional replacement window.
Acoustic glass vs triple glazing
This is one of the most common questions homeowners have when considering their options.
The simplest way to think about it is:
Standard double glazing |
Acoustic glazing |
Triple glazing |
|
Main purpose |
General insulation |
Noise reduction |
Maximum thermal insulation |
Noise reduction |
Good |
Very good |
Good |
Thermal performance |
Good |
Similar to double glazing depending on specification |
Excellent |
Best suited to |
Typical residential properties |
Busy roads and external noise |
Cold or exposed homes |
The manufacturer's figures demonstrate that acoustic glazing can outperform the standard triple-glazed specification for sound reduction.
However, this doesn't mean acoustic glazing is "better" than triple glazing in every respect.
The two products are designed to solve different problems.
If heat loss is your main concern, triple glazing is generally the better choice. If noise is your main concern, acoustic glazing is generally the more appropriate option.
Does acoustic glass improve thermal efficiency?
Compared to old windows, yes, though not necessarily when compared to standard double glazing.
This is another important distinction.
Acoustic glass is primarily designed to reduce sound, rather than heat loss. However, acoustic glazing can still incorporate features such as Low-E coatings and argon gas, meaning its thermal performance can remain similar to that of a modern energy-efficient double-glazed unit.
In the manufacturer information supplied to us, the acoustic double-glazed units have U-values around 1.3–1.4 W/m²K, depending on the window system.
By comparison, the supplied triple-glazed specifications achieve U-values around 1.0–1.1 W/m²K.
Therefore, if maximum thermal efficiency is your objective, triple glazing has the advantage.
If noise is the issue, acoustic glazing provides a more targeted solution without necessarily requiring you to move to triple glazing.
Who should consider acoustic glazing?
Acoustic glass can be particularly worthwhile if your home is affected by persistent external noise.
You may want to consider acoustic glazing if you live:
Near a busy road
Traffic noise is one of the most obvious reasons homeowners consider acoustic windows.
If you can regularly hear cars, buses, lorries or motorcycles from inside your home, acoustic glazing could help reduce the amount of road noise entering through your windows.
Near a railway line
Railway noise can be particularly noticeable because of the combination of engine noise, wheel noise and sudden changes in volume as trains pass.
Acoustic glazing can provide an additional barrier between your home and the railway.
Near an airport or flight path
Aircraft noise can be intrusive, particularly in bedrooms and living spaces.
Acoustic glazing can help reduce the amount of external aircraft noise entering your home.
In a busy town or city
You don't need to live directly beside a motorway to benefit.
Road traffic, pedestrians and general activity can all contribute to background noise, particularly in densely populated areas.
In a room where quiet matters
Bedrooms, home offices and living rooms are often the spaces where external noise is most frustrating.
If a particular room is affected more than others, acoustic glazing could be considered for those windows rather than necessarily upgrading every window in the property.
Is acoustic glass worth it?
If external noise is affecting your enjoyment of your home, acoustic glass can be worth the additional investment. However, it isn't necessarily something every homeowner needs.
If you live on a quiet residential street and external noise isn't a problem, standard modern double glazing will likely provide everything you need.
On the other hand, if you're regularly disturbed by traffic, trains, aircraft or other persistent noise, paying more for glazing specifically designed to reduce sound can make much more sense.
The important thing is to identify what problem you're actually trying to solve.
If you want:
- Better thermal efficiency: consider triple glazing.
- Good all-round performance at a sensible price: modern double glazing can be an excellent choice.
- Reduced external noise: acoustic glazing is the specialist option.
- Both thermal efficiency and noise reduction: an acoustic specification can be combined with an appropriate high-performance glazing system, or acoustic triple glazing can be considered where available.
Should I get acoustic glass?
There isn't a universal answer.
We'd recommend considering acoustic glass if you can clearly identify external noise as one of the reasons you're looking to replace your windows.
For example, if you're sitting in your living room and can clearly hear traffic through your existing windows, acoustic glazing is worth discussing.
If you can't hear much external noise in the first place, the additional cost may be better spent elsewhere.
It's also worth remembering that windows aren't the only route through which sound can enter a property. Walls, doors, roofs and other openings can all contribute to the overall noise level.
This means acoustic glazing can significantly improve the noise performance of your windows, but it cannot guarantee that you will eliminate all external noise from your home.
Does acoustic glass make windows completely soundproof?
No.
This is an important distinction between noise reduction and soundproofing.
Acoustic glazing is designed to reduce the amount of external sound entering through the window. It does not make a room completely silent.
The overall result will depend on factors including:
- The type and volume of external noise
- The glazing specification
- The window frame
- The quality of the window seals
- The installation
- Other potential routes for sound to enter the property
A properly specified acoustic window can make a noticeable difference, but it is unrealistic to expect any replacement window to completely eliminate external noise.
Does acoustic glass work for traffic noise?
Yes. Traffic noise is one of the most common situations where acoustic glazing can be useful.
If you live beside a busy road, the combination of laminated acoustic glass and different glass thicknesses is designed to provide improved sound reduction compared with standard glazing.
The extent of the improvement will depend on the type of traffic noise and the complete window specification, but acoustic glazing is specifically intended for situations where reducing external noise is a priority.
Does acoustic glass work with uPVC windows?
Yes.
Acoustic glazing can be incorporated into modern uPVC window systems, subject to the requirements of the particular frame and glass specification.
The precise performance will depend on the combination of frame, glass and window configuration.
Can you have acoustic glass in double glazing?
Yes.
In fact, acoustic double glazing can be an effective solution where noise reduction is the primary objective.
The acoustic specification supplied by our manufacturer uses two panes of different thicknesses rather than simply adding a third pane.
This can make acoustic double glazing a particularly useful alternative for homeowners who have been told that triple glazing is the obvious answer to external noise.
Is acoustic double glazing more expensive?
Acoustic glazing generally costs more than a standard double-glazed specification because it uses specialist laminated acoustic glass.
However, if reducing noise is your main objective, the additional investment can be more targeted than paying for triple glazing primarily designed to improve thermal performance.
The right choice ultimately depends on your property, the level of noise you're experiencing and your priorities.
Acoustic glazing: the bottom line
Acoustic glass isn't simply "quieter glass" and triple glazing isn't automatically "thicker glass".
The design of the glazing unit matters.
By using laminated acoustic glass, different pane thicknesses and an appropriate cavity, acoustic glazing is specifically engineered to reduce external noise.
For a homeowner living beside a busy road, railway line or another significant source of external noise, it can be one of the most effective upgrades to consider when replacing windows.
Meanwhile, triple glazing remains an excellent choice when the priority is thermal efficiency.
If noise is the problem, choose a glazing specification designed to tackle noise. If heat loss is the problem, choose a specification designed to tackle heat loss.
At Balhousie Glazing, we can help you understand which glazing specification is most appropriate for your property rather than simply recommending the most expensive option.
If you're considering replacing your windows and would like to find out whether acoustic glazing could make a difference to your home, contact our team for advice and a quotation. All our supply-and-fit products are protected by an insurance-backed guarantee, ensuring complete peace of mind for years to come.
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