What does window frame replacement cost in the UK in 2026?
Last updated: April 2026
Window frame replacement is closely related to double glazing installation — in the UK, frames and glass are almost always replaced together as a sealed unit. Whether you're replacing ageing uPVC frames that have warped or discoloured, upgrading timber sash windows in a Victorian terrace, or modernising with slim aluminium frames, the process and costs are similar.
Frame costs vary significantly by material: uPVC is the most affordable at £400–£800 per window, aluminium runs £700–£1,400, and timber can reach £800–£2,000 or more for bespoke joinery. All must be installed by a FENSA or CERTASS-registered company to comply with Building Regulations Part L.
UK homeowners in conservation areas or listed buildings face additional restrictions — timber or approved slim-profile aluminium frames may be required, and planning permission may be necessary even for like-for-like replacements.
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This is an estimate based on average 2026 prices. Actual costs may vary. Always request multiple quotes for an exact price.
Cost factors
Window frame replacement costs per window in the UK, including glazing, supply, and installation.
- uPVC frame (standard casement, supply and fit): £400–£800
- uPVC sash frame (Victorian/Edwardian style): £600–£1,200
- Aluminium frame (slim profile): £700–£1,400
- Timber frame (softwood, painted): £800–£1,800
- Bespoke timber/hardwood frame: £1,200–£2,500+
- Full house (10 windows, uPVC): £5,000–£10,000
All prices include double-glazed sealed unit, installation, and FENSA certificate. Triple glazing adds 20–30% to the above prices.
Why do prices vary?
- Frame material: uPVC: cheapest, no maintenance. Aluminium: premium look, slim sightlines, durable. Timber: traditional, required in conservation areas, needs painting every 5–10 years.
- Window style: Casement windows are the most economical. Sliding sash, bay windows, and curved or arched frames carry a premium.
- Planning restrictions: Conservation areas often prohibit uPVC or aluminium frames — timber or approved slim aluminium only. Always check before ordering.
- Building structure condition: Rotten lintels or damp reveals discovered during frame removal add to costs. Allow a contingency of 10–15%.
- Glazing specification: A-rated double glazing is standard. Triple glazing or acoustic glass (for street noise) adds to cost but improves comfort.
Subsidies & incentives
No dedicated grant exists for window frame replacement in England. In Scotland, Home Energy Scotland offers interest-free loans for window upgrades. Wales and Northern Ireland have support schemes for eligible low-income households. VAT at 20% applies to window replacement — the 0% Energy Saving Materials rate does not apply to glazing. Some households may qualify for windows as part of a broader retrofit through the Warm Homes Local Grant.
Regional price differences
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