When it comes to window sound insulation there are two good choices – either acoustic glass or triple glazing. Here we explain which of the two is best for protecting against sound.
But one thing we have to say from the start: there is no definite answer, because it will depend on various things, like:
- The size of the window
- The window’s shape
- The type of noise that needs to be blocked out
So let’s compare them both and find out which is better in the battle of acoustic glass vs triple glazing.
At a glance: acoustic glass vs triple glazing
| Acoustic Glass | Triple Glazing | |
|---|---|---|
| How it works | Layers of glass and laminate | Three glass panes |
| Noise reduction | Up to 50dB | Up to 40dB |
| Installation | Potentially can keep existing frames | Potentially can keep existing frames |
| Cost | £400 – £2,00 per window | £200 – £800 per window |
| House value | Unlikely to add value | Unlikely to add value |
| Other benefits | Slightly Increased thermal insulation, increased security | Increased thermal insulation, increased security |
Acoustic glass works differently to triple glazing
Both types of windows have been made for a different reason. Acoustic glass is made especially to reduce noise pollution, whereas triple glazing is an improvement of double glazing. With a different aim comes a different functionality.
Triple glazing has three panes of glass with airspace in between. The glass panes absorb some of the sound and thereby reduce the amount that enters your home.
Acoustic glass is made up of two or more layers of glass, with a layer of laminate – though some windows use acoustic foam – sandwiched in between. The glass panes tend to be of different thickness to further interrupt sound passing though.
This combination of different layers has been designed to reflect, dampen and absorb sound waves.
The laminate is used to toughen the glass to help improve its acoustic properties and help prevent it from breaking should an object hit it.
The most common type of laminate is polyvinyl butyral (PVB) which delivers a strong bind for the panes of glass to absorb sound but does not compromise on optical clarity.
Difference in noise reduction
It’s probably no surprise to hear that acoustic glass is better at preventing noise pollution from outside. After all, that’s what it’s been made for.
On average, acoustic windows can absorb up to 50 decibels (dB), while triple glazing can reduce incoming noise by up to 40dB. However, this can vary depending on the manufacturer as it depends on various factors, such as:
- Thickness of glass
- Number of laminated glass panes
- Depth between the glass panes
It has to be said that double glazing can also reduce noise pollution by up to 40dB. However, not all double-glazed windows are made equal. Based on a study by Garg et al. (2012), they were found to be less effective at blocking out vehicle noise if they had an air gap of less than 30mm.
So it’s not just about number of glass panes when it comes to noise reduction. If you already have thicker double-glazed windows and still can hear a lot of road noise from outside, triple glazing might not be enough. You might have to consider acoustic windows.
Sound Transmission Class Rating
The sound transmission class (STC) rating is a way to compare soundproof windows.
Essentially, the pricier acoustic windows will have a higher STC rating but will be effective in blocking out unwanted noise.
The rating is used to measure sound insulation in the wall assembly, so there will be a figure for the materials used for doors, floors and ceilings, and interior partitions.
Understanding the STC rating – and how it impacts the price of acoustic windows – is probably the most important aspect of considering whether to install acoustic windows or not.
However, there’s no point in compromising on the STC figure to save money if you live by a busy, noisy road, for example, when triple glazing may offer a more cost-effective solution if there is a level of noise you are happy to put up with.
Installing Triple Glazing Vs Acoustic Glass
For both these options, there is the possibility that you can just replace your existing double glazing but keep the frames, which can bring costs down considerably. However, this is only possible if the frames have the right size and are capable of supporting the new glass.
Your double-glazing window frames may not be able to support acoustic glass, which tends to have thicker glazing and is heavier.
In cases like this, frames are more important than you think. Ill-fitting frames may be doing more harm than good for insulation and noise reduction. In this case, you’d be better off ditching them (Tadeu & Mateus, 1999).
For acoustic glazing to work effectively, you need to have the window frame and its surrounding area acoustically treated also. So by keeping your double gazing window frames, you might not solve the noise problem.
It’s worth speaking with a firm with experience in fitting acoustic window panes, as they will be able to advise on what you will need.
It’s the same with triple-glazed panes. Because they have an extra glass pane, they are likely to be thicker. If they aren’t, that’s probably because the space between the panes is smaller.
While this means that you can fit them into your double glazing frames, it also means that it probably won’t make much difference in terms of noise cancellation or insulation.
We got told this by a window installer. We opted for triple glazing when we replaced one of our windows, thinking that it would help insulation. But we didn’t make this clear to the window fitter, so we ended up with a triple glazed window that is no better in insulating our home than the double-glazed one.
Noise reduction isn’t a problem for us, as we live rural, where it’s peaceful and quiet anyway. But our experience does show that it’s important that you tell the trades person what you want to achieve, so they can help you make the right decision.
Difference In Price
While there is now getting away from the fact that acoustic windows are more expensive than triple glazed windows, the exact prices for both types of windows can vary.
The cost will depend on:
- Number of windows
- Size of windows
- Type of windows (sash, casement, bay, tilt and turn, etc.)
- Material of frame (wood, uPVC, metal)
This makes it difficult to pin down an average price per window for each type. However, for a triple-glazed window you can expect to be charged anywhere between £200 and £800, but it could be more expensive.
The average price for this is around £400 for every window but if your frames are old, then you may find that installing secondary glazing may not be possible.
The price of soundproof acoustic windows can range from £900 to nearly £2,000 for each one.
And if you opt for stylish soundproof acoustic sash windows, you could be looking at a bill of between £1,400 to nearly £5,000 for each window.
It is a relatively new technique for the glazing industry. As recently as 2024, Wang et al. improved the standard PVB film by combining it with thermoplastic polyurethane in one composite layer. The product resulted in better safety (passed the falling ball test) and noise reduction (up to 20–41 dB).
And new technology tends to be more expensive, so if you go for one of the newest versions, you might have to pay thousands of pounds for one window, although it will probably reduce noise from outside quite considerably.
Effect On Vlaue Of Property
The installation of either acoustic glass or triple glazing will affect the value of a house. However, probably not in the way that you would hope, as it won’t add value in the same way as an extension or a converted garage would.
New windows throughout a property will add value, because it’s one less thing to worry about for the buyer. However, it’s unlikely to add enough to cover the cost of installation and certainly not more.
With Energy Performance Certificates (EPCs) legally required for all properties up for sale, buyers are increasingly putting higher values on more energy efficient homes. Therefore, a triple glazed property is likely to attract more interest and a slightly higher sales price than ones without it.
Acoustic glass windows might not add much value, but they can stop your home from losing value. If you live on a very busy road or noisy neighbourhood, this will push down the price.
However, if the acoustic windows can reduce the noise levels inside the home enough, the property is likely to fetch a higher price than similar ones in the same area without them.
So the question of adding value is a rather complicated one. On the whole, we would say that adding value shouldn’t be a consideration when thinking about installing acoustic glass vs triple glazing, as neither is likely to add a huge amount of value.
Additional Benefits
We have talked about the sound reducing abilities of both acoustic glass and triple glazed windows. But if you are trying to decide between the two, you might be interested in other benefits they have.
Thermal insulation
Triple glazing has been developed to offer better thermal insulation than double glazing. According to Rightmove, triple glazing is 40% to 50% more energy efficient than older double glazing. This means replacing old double-glazed windows with triple glazing can keep your home warmer and reduce your energy bills.
Newer double-glazed windows will have a similar energy efficiency as triple glazing, so the difference might not be as big. It’s worth checking with a professional window fitter to see if changing to triple glazing would make your home more energy efficient.
Acoustic glass windows do also offer some thermal insulation properties, but not as much as triple glazing. After all, it has been designed to reduce noise entering your home not heat leaving it.
Increased Security
Both acoustic glass and triple glazing will be more difficult to break. Triple glazing because there are three panes of glass and acoustic glass because the laminated glass is stronger.
So whichever you install, it will make them more difficult to smash and break into your home. This is one of the reasons we went with triple glazing. In particular, the downstairs windows we wanted to be stronger to give us peace of mind.
Acoustic Glass Vs Triple Glazing – Which One To Choose
There is a lot of debate about which is better acoustic glass or triple glazing. As we have seen, acoustic glass is better at reducing noise levels than triple glazing, even if the latter can also reduce the noise levels in your home, especially if you have older double-glazed or single windows.
Which one is the better option for you will depend on your individual needs:
- How noisy is it in your property?
- What’s your budget?
- Do you also want to improve energy efficiency?
In some circumstances, triple glazing might be sufficient to reduce the noise in your home. But if your location is especially noisy, you could consider only installing acoustic glass in the room you need the peace and quiet the most, like your bedroom.
This could help with budget constraints while still giving you a quiet place.
If you want to reduce noise and benefit from cheaper heating bills, then triple glazing is certainly worth considering, as long as it will reduce the noise enough for your needs.
Whichever route you consider, it’s always worth speaking to at least one glazing company about their window products and how they can improve the noise pollution levels in your home.
