Acoustic glazing: what laminated windows really do for noise

Quick answer: Acoustic laminated double glazing manages a lab-tested Rw of 36 to 40dB against 28 to 32dB for standard units, and a 10dB gain sounds roughly half as loud. Expect £90 to £260 extra per window. For severe noise, secondary glazing at Rw 44 to 50 beats triple glazing comfortably.

How is window noise reduction actually measured?

The honest unit is Rw, the weighted sound reduction index. It’s a laboratory figure measured across the frequencies that make up everyday noise, and it lets you compare glazing like for like. Marketing prefers percentages. “Reduces noise by up to 90%” tells you almost nothing, because it names no starting point and no frequency.

If a glazing quote doesn’t state an Rw figure, the noise claim can’t be checked. Ask for it in writing. Two other rules of thumb help: 3dB is a just-noticeable change, and 10dB reads to the human ear as roughly half the loudness.

What does laminated acoustic glass do differently?

Ordinary laminated glass is two panes bonded with a plastic interlayer, originally for safety. Acoustic laminated glass swaps in a PVB interlayer tuned to damp sound instead of just holding shards together. Glazing supplier Vitrums (checked August 2026) notes the acoustic interlayer targets the 500 to 3,000Hz band, which is where traffic noise concentrates.

Pairing it with panes of different thicknesses helps again, since identical panes resonate at the same frequency and wave sound straight through. An asymmetric unit with one acoustic laminated pane is the strongest sealed-unit format you can buy.

The numbers: glazing types compared for noise

These are Vitrums’ published lab ranges and supply-and-fit uplifts per window. We haven’t lab-tested glazing ourselves; this is published data, checked August 2026.

Stepping from standard double to acoustic asymmetric buys around 8dB, approaching the 10dB your ears register as halving the noise. On a busy road that’s the difference between hearing every lorry and hearing a murmur. For whole-window budgets, see window replacement costs.

Is triple glazing better for noise?

Usually not, and it surprises people. Vitrums’ figures put standard triple at 35 to 39dB, level with mid-range acoustic laminated double and short of the best acoustic asymmetric units. The third pane adds weight and cost but also a second identical cavity, which does little for sound.

Triple glazing is a heat product, not a noise product. Buy it for U-values and comfort, per our double vs triple glazing comparison, and buy laminated glass for sound. If a salesperson leads with noise as the reason to go triple, that’s a tell.

When is secondary glazing the right call?

When the noise is severe, or the windows can’t change. A secondary pane set 50 to 200mm inside the original window decouples the two layers, and Vitrums rates well-fitted systems at Rw 44 to 50, the best results of any option. That’s why it’s the standard fix under flight paths and on arterial roads, and often the only permitted fix in listed buildings and conservation areas.

The trade-offs are looks and sills you can’t use the same way. Our secondary glazing comparison weighs both routes. For plain noise reduction per pound, secondary glazing beats replacing the windows.

How do you work out what you need before getting quotes?

Start by naming the enemy. Constant tyre roar, intermittent sirens, aircraft, a pub garden: they sit in different frequency bands and peak at different times, and a surveyor who asks about none of that is guessing.

A phone sound-meter app gives a rough sense of levels at the window, morning and night. It’s not calibrated kit, but it turns “it’s noisy” into “it’s worst at 7am and it’s low rumble”, which is genuinely useful when comparing proposals. A serious acoustic glazing quote responds to your specific noise, not a generic percentage claim. If every house on the street would get the same recommendation, keep shopping.

Will better glass fix the noise on its own?

Only if the glass was the weak point. Sound flanks: through trickle vents, gappy seals, letterboxes, and party walls. A 43dB window in a wall with an open vent performs like the vent.

So spend in order. Seal and draught-proof first, then glazing, then the structure. If the noise comes through a party wall, no window will touch it, and you’re into wall and floor soundproofing territory instead. For a broader tour of the options, start with our guide to windows and noise reduction.

FAQs

Can acoustic glass go into my existing frames?

Often, if the frames are sound and the new unit’s thickness fits the rebate. Acoustic laminated panes are thicker than the 4mm glass they replace, so it’s a question for the surveyor rather than a given.

Does laminated glass help with security too?

Yes. The interlayer holds the pane together under impact, so a break becomes a spiderweb rather than a hole. It’s the same construction logic as a car windscreen.

What Rw should I aim for on a busy road?

Aim for 40dB or better, which in practice means acoustic asymmetric double glazing or secondary glazing. Below that you’ll hear the improvement but still hear the road.