Soundproofing windows costs £200–£2,500 per window depending on the method you choose
If traffic, neighbours, or aircraft noise enters your home through the windows, you have several options to reduce it. The cost and effectiveness vary significantly by method.
Soundproofing a room window costs £200–£2,500 per window depending on the method. Secondary glazing (£200–£800) is the most cost-effective retrofit, reducing noise by 35–50 dB. Compare options to find the best fit for your noise type and budget.
- Secondary glazing costs £200–£800 per window installed.
- Acoustic laminated glass replacement runs £500–£2,500 per window.
- Secondary glazing reduces noise by 35–50 dB, better than double glazing.
- DIY acoustic curtains cost £50–£150 but cut only 5–10 dB.
- Wider air gap in secondary glazing improves low-frequency noise reduction.
- Soundproofing windows costs £200–£2,500 per window depending on the method you choose
- Secondary glazing reduces noise by 35–50 dB and is the most cost-effective retrofit option
- Acoustic laminated glass replacement achieves 30–40 dB reduction but requires full unit replacement
- Quick numbers key soundproofing options compared
- The single most effective fix for road or aircraft noise is secondary glazing with a 200 mm air gap
- You must check MCS certification for secondary glazing installers to qualify for any available grants
- Budget soundproofing acoustic curtains or DIY window plugs cost under £200 but cut noise by only 5–15 dB
Secondary glazing is the most popular retrofit option, typically costing £200–£800 per window installed, while replacing existing glass with acoustic laminated glass runs £500–£2,500 per window (Energy Saving Trust, 2026). DIY acoustic curtains or heavy drapes start at £50–£150 per window but offer limited noise reduction of around 5–10 dB (FENSA, 2026). The exact cost depends on window size, existing frame condition, and whether you need trickle vents or other ventilation solutions.
Secondary glazing reduces noise by 35–50 dB and is the most cost-effective retrofit option
Secondary glazing adds a second pane of glass 100–200 mm from the existing window, creating an air gap that dampens sound transmission. Typical noise reduction is 35–50 dB for secondary glazing, compared to 25–35 dB for standard double glazing (BRE, 2026).
This method can be fitted to any window type including sash, casement, and tilt-and-turn without replacing the original frame. The air gap is the key factor: a wider gap delivers better sound reduction, especially for low-frequency noise like traffic or aircraft rumble (MCS Register, 2026). Secondary glazing also improves thermal insulation, which may help with energy bills.
Acoustic laminated glass replacement achieves 30–40 dB reduction but requires full unit replacement
Replacing existing sealed units with acoustic laminated glass adds mass and damping to the window. Typical thickness is 6.8 mm or 10.8 mm, and the glass contains a special interlayer that absorbs sound vibrations (Glass and Glazing Federation, 2026).
Cost ranges from £500–£2,500 per window, including frame adaptation if needed. However, this method is less effective than secondary glazing because the air gap in a sealed unit is fixed at 12–20 mm, and sound can bypass the glass through the frame (GOV.UK, 2026). Acoustic laminated glass works best for high-frequency noise such as voices or alarms, but struggles with low-frequency rumble.
Quick numbers key soundproofing options compared
| Method | Typical cost per window | Noise reduction (dB) | Installation time | Ventilation impact |
|---|---|---|---|---|
| Acoustic curtains | £50–£150 | 5–10 dB | 30 minutes | Blocks airflow |
| DIY window plug | £30–£80 | 10–15 dB | 1 hour | Removes ventilation |
| Secondary glazing | £200–£800 | 35–50 dB | 2–4 hours per window | Can include trickle vent |
| Acoustic laminated glass | £500–£2,500 | 30–40 dB | 1–2 hours per unit | Standard trickle vent |
Sources: Energy Saving Trust, 2026; FENSA, 2026; BRE, 2026.
The single most effective fix for road or aircraft noise is secondary glazing with a 200 mm air gap
For low-frequency noise such as traffic or aircraft, the air gap between the existing window and the secondary pane matters more than glass thickness. A 200 mm air gap delivers the best sound reduction, outperforming thicker glass alone (BRE, 2026).
For high-frequency noise like voices or alarms, thicker glass adds benefit. A 10.8 mm laminated pane in the secondary glazing system improves performance for these sounds (Energy Saving Trust, 2026). If you cannot achieve a 200 mm gap, a minimum of 100 mm still provides significant reduction. The frame must be sealed properly to prevent sound leakage through gaps.
how to choose between secondary glazing and double glazing
You must check MCS certification for secondary glazing installers to qualify for any available grants
MCS (Microgeneration Certification Scheme) covers secondary glazing installers for grants such as ECO4 or the Great British Insulation Scheme. Without MCS certification, you cannot claim these grants (GOV.UK, 2026).
TrustMark is the government-endorsed quality scheme for all home improvement work. FENSA registration is required for replacement sealed units to comply with building regulations (FENSA, 2026). Always request written certification and check the installer on the MCS or FENSA register before paying. If you are a tenant, check your tenancy agreement before making any permanent changes.
what grants are available for home improvements in 2026
Budget soundproofing acoustic curtains or DIY window plugs cost under £200 but cut noise by only 5–15 dB
Acoustic curtains use mass-loaded vinyl backing to absorb sound. They reduce high-frequency noise such as voices or alarms but do little for low-frequency rumble from traffic or aircraft (BRE, 2026).
DIY window plugs are foam board cut to fit the window recess, often covered in fabric for appearance. They block sound completely but remove all ventilation. Neither option is likely to satisfy noise nuisance complaints for planning or rental issues (GOV.UK, 2026). If you need a permanent solution, secondary glazing or acoustic glass replacement is more reliable.
Frequently Asked Questions
Secondary glazing is the most effective retrofit, reducing noise by 35–50 dB according to BRE (2026). It works well for low-frequency traffic rumble because the air gap dampens sound transmission.
Costs range from £200–£800 per window for secondary glazing, £500–£2,500 for acoustic laminated glass, and £50–£150 for DIY curtains (Energy Saving Trust, 2026). Exact price depends on window size and frame condition.
Yes, secondary glazing typically reduces noise by 35–50 dB, compared to 25–35 dB for standard double glazing (BRE, 2026). The wider air gap (100–200 mm) gives better soundproofing.
Yes, secondary glazing is a retrofit option that fits over existing windows without frame replacement. It works with sash, casement, and tilt-and-turn types (MCS Register, 2026).
Acoustic curtains or heavy drapes start at £50–£150 per window (FENSA, 2026). They offer limited noise reduction of 5–10 dB but are the lowest cost option.
