What Does Window Replacement Cost?
Quick Answer
uPVC casement £350–£550 per window, supplied and fitted
Standard medium window (about 900 × 1200mm), double glazed. Timber sash runs £1,200–£3,500. Guide prices from published 2026 UK cost guides, not quotes
Cost per Window by Material (2026 UK)
The table collates MyJobQuote (May 2026) and Checkatrade (2026) fitted prices for a medium double-glazed window. Where the two disagree, the range shows the full spread.
| Window type | Guide price (fitted) | Notes |
|---|---|---|
| uPVC casement | £350–£550 | White; the cheapest and most common choice (Checkatrade £350–£520, MyJobQuote £350–£550). Large 1200 × 1200mm units run £550–£700 |
| uPVC sliding sash | £500–£1,100 | Checkatrade £500–£800, MyJobQuote £700–£1,100 |
| Aluminium casement | £450–£850 | Guides disagree here: Checkatrade’s average is about £475 while MyJobQuote quotes £600–£850 for a medium unit |
| Aluminium sash | £800–£1,500 | Slim sightlines for period-style openings |
| Timber casement | £750–£1,100 | Checkatrade’s average for a 600 × 900mm unit is about £925 |
| Timber sliding sash | £1,200–£3,500 | Softwood £1,200–£2,500 fitted, hardwood £1,800–£3,500 (specialist sash guides); MyJobQuote’s standard band is £1,500–£2,000. The usual conservation-area choice |
| Bay window (3-section uPVC) | £1,500–£2,500 | MyJobQuote’s band; size the structural opening with the bay window calculator |
Whole-House Costs: the Guides Disagree
This is where published figures split most. MyJobQuote prices a 3-bed semi (8–10 windows) at around £3,750 in white uPVC and a 4-bed detached (10–15 windows) at £5,500–£7,000, while Checkatrade’s 2026 figure for a typical 3-bed house (8–12 windows) is £8,000–£15,000, and other guides land between (£4,000–£8,500). All are current guides, so treat anything from about £3,750 to £15,000 as a plausible whole-house uPVC quote depending on window count, sizes and installer, and compare at least three itemised quotes. Timber whole-house jobs run £10,000–£16,000 and upwards.
What Affects Window Price
- Size: price scales with glass area; bays and large fixed lights cost significantly more
- Glazing spec: triple-glazed uPVC casements run about £550–£900 per window fitted (MyJobQuote); check whether you need it with the window U-value calculator
- Colour and finish: anthracite, black and woodgrain foils add roughly 10–15% on uPVC
- Opening style: sashes and tilt-and-turn cost more than fixed or side-hung casements
- Access: upper floors needing scaffold or towers add cost; see scaffold hire costs
- Acoustic glass: for noise, compare laminated acoustic units with the acoustic glazing calculator, or consider secondary glazing
Building Regulations
- Replacement windows in an existing dwelling must meet Part L: U-value 1.4 W/m²K or better, or Window Energy Rating Band B (AD L 2021, Table 4.2). Check yours with the window energy rating calculator
- Use a FENSA or Certass registered installer, or pay building control to inspect and certify the work
- Part F 2021: replacement windows normally need trickle ventilators at least equivalent to any existing provision; size them with the trickle vent calculator
- First-floor bedrooms need escape-compliant openings; check with the window fire escape calculator
London and the South East
Installer day rates in London run well above the national average (MyJobQuote quotes about £300 per day for a London fitter against £175–£300 elsewhere, with two-person teams at £350–£600 per day), so whole-house quotes in London and the South East typically land in the upper half of every range on this page.
Important Notes
- All figures are guide prices from published 2025–2026 UK cost guides, not quotes: whole-house pricing varies widely, so get at least three itemised quotes
- Like-for-like replacements in conservation areas may still need consent; check before ordering
- Keep the FENSA/Certass certificate: buyers’ solicitors ask for it
Figures cross-checked against published UK cost guides July 2026. Last updated: July 2026