Glass and upgrades

Acoustic triple glazing

If noise is the main reason you are looking at triple glazing, the glass spec matters more than the number of panes. A standard double unit cuts sound by about 29 dB (Rw); standard laminated units reach about Rw 32 to 34 dB, units with an acoustic interlayer usually reach the mid to high 30s, and a well-specified acoustic triple unit can go further. Every 3 dB is a noticeable step.

Lead time: 4 to 6 weeksGuide from: £745 inc VAT

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Quiet bedroom at dusk with a closed white window overlooking a busy main road

Summary

Acoustic triple glazing combines a three-pane unit with at least one laminated acoustic pane and panes of different thickness, which together reduce traffic and aircraft noise more than a standard unit. The third pane on its own adds only a few decibels; the laminated pane and the airtightness of the frame do most of the work.

What you get

Glass	Triple unit with laminated acoustic pane(s)
Pane thicknesses	Mixed, e.g. 6.4 mm laminated / 4 mm / 6 mm
Standard double (4/16/4)	About Rw 29 dB
Laminated acoustic units	About Rw 33 standard laminated; mid to high 30s with an acoustic interlayer
Frame	Airtight multi-seal frame, acoustic trickle vents
Typical lead time	4 to 6 weeks

Guide prices

Guide prices per sealed unit or window, fitted.

Small window

about 600 x 1000 mm (bathroom, landing)

£745 – £895inc VAT · £620 – £745 ex VAT

uPVC frame, triple glazed, warm-edge spacers
Removal and disposal of the old window
Fitted, sealed and made good inside and out

Mid-size

Medium window

about 1200 x 1200 mm (bedroom)

£1,095 – £1,295inc VAT · £910 – £1,080 ex VAT

uPVC frame, triple glazed, warm-edge spacers
Removal and disposal of the old window
Fitted, sealed and made good inside and out

Large window

about 1800 x 1200 mm (lounge)

£1,595 – £1,895inc VAT · £1,330 – £1,580 ex VAT

uPVC frame, triple glazed, warm-edge spacers
Removal and disposal of the old window
Fitted, sealed and made good inside and out

Guide prices, supply and fit. The written quote after your survey fixes the price for the specification shown; anything extra is agreed with you first.

Is it right for your home?

A good fit for

Homes on main roads, rail lines or flight paths
Bedrooms facing the noise
Flats above busy streets

Think twice if

Rooms where the noise comes through walls or vents, not windows
Expecting silence: glazing reduces noise, it does not remove it

Options

Acoustic trickle vents
Laminated inner pane for security too
Mixed-thickness panes
Upgraded seals and fitting
Acoustic secondary glazing where replacement is not allowed

What actually reduces noise

Sound gets through the weakest path. Laminated glass with an acoustic interlayer damps vibration, panes of different thickness stop the unit resonating at one frequency, and a well-sealed frame stops sound leaking round the edges. A standard trickle vent is a sound leak, so acoustic vents are specified where vents are needed.

Choosing which rooms to upgrade

Acoustic glass costs more, so many people use it only on the rooms facing the noise, usually front bedrooms. The rest of the house can have standard triple glazing.

Building Regulations by nation

Nation	Replacement windows	Sign-off
England	1.4 W/m²K, or a Window Energy Rating of band B or better	Competent person scheme or building control
Wales	1.4 W/m²K, or a Window Energy Rating of band B or better	Competent person scheme or building control
Scotland	1.6 W/m²K	No building warrant for a straight replacement; must meet the standards
Northern Ireland	1.6 W/m²K, or a Window Energy Rating of band C or better	No building notice for a straight replacement; must comply

Full regulations guide, with sources →

Questions about acoustic triple glazing

Does triple glazing reduce noise more than double?

A little: the third pane adds about 3 dB, sometimes less. Laminated acoustic glass makes the bigger difference, whether in a double or triple unit.

How much extra is acoustic glass?

Comparing our guide prices, acoustic glass adds about £50 to £200 a window, inc VAT, depending on size.

Will acoustic glazing block all traffic noise?

No glazing makes a room silent. Well-specified acoustic glazing makes a clear, noticeable reduction, especially in the low rumble of traffic.

Do trickle vents let noise in?

Standard vents can. Acoustic trickle vents are designed to keep ventilation while reducing sound.