Calculate your window replacement cost
Double-glazed window cost by type in Belfast
UK £500–£1,250 · avg £1,000£484–£1,200 · avg £950
UK £700–£1,500 · avg £1,200£700–£1,450 · avg £1,150
UK £600–£1,400 · avg £1,100£600–£1,350 · avg £1,050
UK £600–£1,400 · avg £1,100£600–£1,350 · avg £1,050
UK £1,100–£4,000 · avg £2,500£1,050–£3,850 · avg £2,400
UK £1,500–£5,000 · avg £3,000£1,450–£4,850 · avg £2,900
Whole-house double glazing
What can change a real Belfast 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
Northern Ireland has different policy and grant arrangements from Great Britain, so scheme-specific calculator assumptions should be checked carefully.
- Northern Ireland regulations, approvals and support schemes should be checked independently from England, Wales and Scotland guidance.
- Regional material supply, specialist-trade availability and travel can affect individual quotes beyond the broad model factor.
- For major refurbishment, keep surveys, remedial work and compliance costs separate from visible finish upgrades.
How the regional model works
The broad Northern Ireland factor is 0.89×, but the live window calculator applies only 30% of that regional difference because replacement-window pricing has a large manufactured-product component. The resulting Belfast window factor is 0.967×.
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 Belfast 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 Belfast range is £7,750–£14,500.
How much do 10 casement windows cost in Belfast?
The national casement benchmark is £500–£1,250 per window. For 10 windows, the calculator's moderated regional factor gives £4,850–£12,100, before triple-glazing or scaffolding allowances.
Why is the Belfast 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.