Secondary Glazing Cost Guide
Straight answers on what secondary glazing costs in the UK — by window size, system and glass specification.
How much does secondary glazing cost?
In the UK, secondary glazing typically costs £163 – £680 per window, fully fitted, depending on the system, glass specification and opening size. Bespoke shapes and heavy-duty commercial units sit higher; small lift-out panels sit lower.
There is no scaffolding, no external work and no need for replacement joinery, so the headline figure is close to the finished price — no hidden extras.
Price by system and window size
Ranges below assume standard 4mm toughened glass, white powder-coated aluminium and installation as part of a typical project. Add the glass uplifts in the next table for acoustic or thermal upgrades.
| Window size | Horizontal slider | Vertical slider | Hinged casement | Lift-out panel | Vision (arched) |
|---|---|---|---|---|---|
| Small (up to 0.5m²) | £163 – £245 | £280 – £395 | £210 – £320 | £145 – £215 | £320 – £460 |
| Medium (0.5 – 1.5m²) | £245 – £420 | £395 – £620 | £320 – £510 | £215 – £360 | £460 – £720 |
| Large (1.5m² +) | £420 – £680 | £620 – £960 | £510 – £810 | £360 – £580 | £720 – £1,150 |
Prices are typical UK rates for 2026, VAT included. Individual quotes vary with access, colour, glass and volume.
Glass upgrades and when they pay off
| Glass specification | Typical uplift | Best for |
|---|---|---|
| 4mm toughened (standard) | Included | General use, hallways, fixed lights |
| 6.4mm acoustic laminated | + £45 – £85 per m² | Main-road frontages, city-centre bedrooms |
| 6.8mm acoustic laminated | + £65 – £115 per m² | Rail, flight-path, nightlife-adjacent |
| Low-E soft-coat thermal | + £35 – £65 per m² | Solid-wall period homes, north-facing rooms |
| Obscure / patterned | + £25 – £55 per m² | Bathrooms, WCs, side-return windows |
Secondary glazing vs replacement double glazing
Like-for-like replacement of a timber sash with a new double-glazed sash unit typically runs £1,800 – £3,500 per window — several times the cost of a secondary glazing install, before scaffolding, planning fees and internal redecoration.
For acoustic performance, secondary glazing usually wins outright: a 100–200mm air-gap beats any sealed 20mm double-glazed unit for cutting mid- and low-frequency noise.
What affects the final quote
- Window size and shape (arched, circular)
- Glass specification (acoustic, Low-E, laminated)
- Frame colour — white is standard, RAL colours add ~5–10%
- Number of openings on the same visit
- Access — high-level, hard-to-reach or scaffolded
- Commercial extras (out-of-hours, phased install, CAD)
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