Why Are Your Windows So Noisy?
Sound travels through windows primarily via the glass. A standard single-glazed sash window offers almost no sound insulation — around 20–24 dB of noise reduction. If you live near a busy road, railway, or under a flight path, that is nowhere near enough. Fortunately, modern glazing technology can reduce noise transmission by 35–45 dB, which translates to a perceived noise reduction of up to 80%.
The key factors that determine acoustic performance are glass thickness, the air gap between panes, the use of laminated glass, and the quality of the window seal. Larger air gaps and asymmetric glass combinations (different thicknesses on each side) break up sound waves more effectively than identical panes.
Glazing Options Compared
| Glazing Type | Noise Reduction | Best For |
|---|---|---|
| Single glazed (original) | 20–24 dB | Nothing — replace it |
| Standard double glazed (4/16/4) | 29–32 dB | General improvement |
| Acoustic double glazed (6.4/16/4) | 35–38 dB | Busy roads, urban noise |
| Triple glazed | 36–40 dB | High noise + thermal needs |
| Acoustic laminated + air gap | 40–45 dB | Severe noise (flight paths, railways) |
| Secondary glazing (added panel) | 40–50 dB | Listed buildings, maximum isolation |
The most effective single upgrade for noise reduction is acoustic laminated glass with an asymmetric configuration. A 6.4mm laminated outer pane paired with a 4mm inner pane and a 16mm air gap provides excellent acoustic performance while maintaining a slim profile suitable for traditional sash windows.
Sash Windows and Sound
Old sash windows are among the worst performers for noise. Gaps around the sashes, worn draught seals, and single glazing all allow sound to pass through freely. Replacing single-glazed sash windows with bespoke double-glazed units typically reduces perceived noise by 50–70%. Adding acoustic laminated glass pushes this further.
Importantly, the frame and seal quality matters as much as the glass. A perfectly glazed window with poor seals will still leak sound. Our sash windows use compression seals on all opening edges, virtually eliminating air gaps and the noise that travels through them.
Secondary Glazing for Listed Buildings
If your property is Listed and you cannot replace the original windows, secondary glazing is the most effective acoustic solution available. A secondary panel installed on the room side of the existing window creates a large air gap (typically 100–150mm) that dramatically reduces sound transmission. This approach can achieve noise reductions of 40–50 dB — better than most replacement windows.
What We Offer
All our timber sash and casement windows are available with acoustic glazing options. Our 3D configurator lets you choose your glass type and see the acoustic and thermal specifications before you order. We offer standard double glazing, acoustic laminated glass, triple glazing, and passive-grade glass.
🇬🇧 Made in UK · 4–5 Week Delivery
Price Your Acoustic Windows
Use our 3D configurator to design your windows with acoustic glazing. Instant price, no account needed.
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