What does double glazing cost in the UK in 2026?
Last updated: April 2026
Double glazing is standard in modern UK homes, but millions of older properties still have single-glazed windows or ageing double glazing that no longer meets current energy efficiency standards. Replacing windows can reduce heat loss through glazing by up to 50%, eliminate condensation on the inside of glass, and significantly improve sound insulation — important in busy urban areas.
In the UK, double glazing costs £400–£1,200 per window depending on size, material (uPVC, aluminium, timber), and glazing specification (double or triple). A full house replacement (8–12 windows) typically runs £5,000–£12,000 for uPVC and £8,000–£20,000 for aluminium or timber frames.
All replacement windows must comply with Building Regulations (Part L) and be installed by a FENSA-registered or CERTASS-registered installer, or alternatively covered by a local authority building notice — otherwise you'll need Building Regulations approval separately.
Know someone considering this project?
Share this cost guide in 5 seconds.
Calculate your estimated costs
This is an estimate based on average 2026 prices. Actual costs may vary. Always request multiple quotes for an exact price.
Cost factors
Double glazing costs per window in the UK, including supply and installation (VAT at 20%).
- uPVC casement window (standard size): £400–£800
- uPVC sash window (Victorian/Edwardian style): £600–£1,200
- Aluminium window (standard size): £700–£1,400
- Timber window (standard size): £800–£2,000
- Full house (8–12 uPVC windows): £5,000–£12,000
- Full house (8–12 aluminium windows): £8,000–£20,000
Prices include FENSA registration and certificate. Triple glazing (recommended for north-facing and exposed elevations) adds 20–40% to costs but can reduce heating bills by a further 10–15%.
Why do prices vary?
- Frame material: uPVC is cheapest and most common. Aluminium offers a slimmer, more modern profile. Timber is traditional and required in many conservation areas but needs more maintenance.
- Window style: Casement windows are the simplest and cheapest. Sash windows (popular in Victorian and Edwardian homes) are more complex and expensive due to their sliding mechanism.
- Glass specification: Standard A-rated double glazing is the minimum for Building Regulations compliance. A++ or triple glazing is better for exposed or north-facing windows.
- Conservation areas and listed buildings: Conservation area or listed building restrictions may require timber frames, specific styles, or planning permission. Costs can be significantly higher.
- Number of windows: Full-house replacement offers economies of scale — per-window cost decreases for larger orders. Always get a total price, not just per-unit quotes.
- Removal and disposal of old windows: Most FENSA installers include removal and disposal in the price — confirm this before signing.
Subsidies & incentives
There is no dedicated double glazing grant in England. However, window upgrades may be funded as part of a broader retrofit package through the Warm Homes Local Grant. In Scotland, the Home Energy Scotland scheme offers interest-free loans of up to £15,000 for energy improvements, including windows. Wales's Nest scheme and Northern Ireland's Affordable Warmth scheme provide support for eligible households. VAT on double glazing is the standard 20% — it does not qualify for the 0% Energy Saving Materials rate.
Regional price differences
Choose a city to view local prices and availability.
Is your city not listed?
View all insulation professionalsFrequently asked questions
Related cost guides
Cavity wall insulation
Cavity wall insulation in the UK costs £700–£2,500 but may be free through ECO4. Find out if your home has cavity walls...
Floor insulation
Floor insulation costs £500–£2,000 in the UK for suspended timber floors and £1,500–£4,000 for solid floors. Find out wh...
Roof insulation
Loft insulation costs £300–£1,000 in the UK, but may be free through ECO4 or the Great British Insulation Scheme. Find o...