What Does Window Replacement Cost?
Quick Answer
£300–£600 per uPVC window (supply & fit)
Aluminium: £500–1,000. Timber: £600–1,200. Based on standard 1200 × 1200mm casement window (2026 UK)
Cost by Window Material (2026)
- uPVC casement: £300–£600 per window (supply & fit)
- uPVC sash: £500–£900 per window
- Aluminium casement: £500–£1,000 per window
- Timber casement: £600–£1,200 per window
- Timber sash: £1,000–£2,000 per window
Whole-House Examples
- 3-bed semi (8 windows): £3,000–£5,000 (uPVC)
- 4-bed detached (12 windows): £5,000–£8,000 (uPVC)
- Victorian terrace sash (6 windows): £6,000–£12,000 (timber sash)
What Affects Window Price?
- Size: Larger windows cost more. Bay windows significantly more
- Glazing spec: Triple glazing adds 20–30% over double
- Opening mechanism: Tilt-and-turn costs more than side-hung
- Colour: Non-white uPVC (anthracite grey, black) adds £30–80 per window
- Access: Upper floors requiring scaffolding add cost
Building Regulations
- Replacement windows must meet Part L thermal performance (U-value 1.4 W/m²K or better)
- Must be installed by a FENSA or CERTASS registered installer (or get Building Control sign-off)
- Trickle ventilators required on all replacement windows
Last updated: April 2026