Calculate your window replacement cost
Double-glazed window cost by type in London
UK £500–£1,250 · avg £1,000£550–£1,350 · avg £1,100
UK £700–£1,500 · avg £1,200£750–£1,650 · avg £1,300
UK £600–£1,400 · avg £1,100£650–£1,500 · avg £1,200
UK £600–£1,400 · avg £1,100£650–£1,500 · avg £1,200
UK £1,100–£4,000 · avg £2,500£1,200–£4,350 · avg £2,700
UK £1,500–£5,000 · avg £3,000£1,650–£5,400 · avg £3,250
Whole-house double glazing
What can change a real London quote?
- Casement, sash, sliding, tilt-and-turn, bay or bow style
- Window dimensions and opening configuration
- uPVC, aluminium or timber frame specification
- Double versus triple glazing
- Number of windows in the order
- Scaffolding or difficult access
- Making good around the openings
Local planning considerations
Dense access, parking, deliveries and contractor overheads can widen the spread between quotations, so use the figures as an early budget rather than a quote.
- Allow separately for parking, loading, permits or restricted delivery windows where a property has difficult street access.
- Flats and managed buildings can add landlord, freeholder or building-management requirements that are outside a basic works estimate.
- Party-wall, structural and access costs should be checked independently on extensions, lofts and major internal alterations.
How the regional model works
The broad London factor is 1.28×, but the live window calculator applies only 30% of that regional difference because replacement-window pricing has a large manufactured-product component. The resulting London window factor is 1.084×.
Sources
Double Glazing Costs in the UK in 2026
Published / checked: May 2026
Used for: Replacement window ranges by window type and whole-house double glazing benchmarks
Frequently asked questions
How much do replacement windows cost in London in 2026?
Current double-glazing benchmarks run from about £500 for a basic casement to £5,000+ for larger specialist bow windows. A typical 3-bedroom whole-house project is around £8,000–£15,000 nationally; the modelled London range is £8,650–£16,250.
How much do 10 casement windows cost in London?
The national casement benchmark is £500–£1,250 per window. For 10 windows, the calculator's moderated regional factor gives £5,400–£13,550, before triple-glazing or scaffolding allowances.
Why is the London window factor smaller than the general regional factor?
Frames and glazing units contain a substantial nationally priced manufacturing component, so the calculator applies only 30% of the broad regional difference.
What can increase a window replacement quote?
Sash, bay and bow windows, aluminium or timber frames, triple glazing, upgraded security glass, difficult access, scaffolding and repairs to existing openings can increase the total.