Double Glazing Cost UK (2026)
Last updated 5 October 2026 · Prices based on the Ofgem price cap (October 2026 – December 2026)
Double glazing cuts heat loss through windows by about half compared with single glazing. The energy saving alone rarely justifies replacing existing double glazing, but for single-glazed homes it is a worthwhile upgrade.
Double glazing cost payback calculator
At £7,000 net cost and £180 saved a year, it pays for itself in about 38.9 years.
- Net cost
- £7,000
- Payback
- 38.9 yrs
- 10-year saving
- £-5,200
Simple payback = (cost − grant) ÷ annual saving, at today's price cap (26.32p electricity, 7.97p gas). Ignores future price changes.
Double glazing cost by property type (uPVC, from single glazing)
| Property type | Typical cost | Annual saving | Payback |
|---|---|---|---|
| Flat (5 windows) | £3,000–£4,500 | £80–£120 | 30+ yrs |
| Terrace (8 windows) | £4,500–£7,000 | £120–£160 | 30+ yrs |
| Semi (10 windows) | £6,000–£9,000 | £150–£200 | 35+ yrs |
| Detached (12+ windows) | £8,000–£12,000 | £200–£250 | 35+ yrs |
Cost per window by frame material
| Material | Per window installed |
|---|---|
| uPVC | £400–£700 |
| Aluminium | £700–£1,100 |
| Timber | £800–£1,400 |
| Secondary glazing | £200–£450 |
What affects the cost
Frame material
uPVC is cheapest; timber suits period homes.
Window size and style
Bay and sash windows cost more.
Glass spec
Low-E coatings and argon fill improve performance.
Listed buildings
May need secondary glazing instead.
How to reduce the cost
- Look for A-rated or better windows
- Consider secondary glazing for listed homes
- Use heavy curtains and blinds at night
- Fit draught strips to existing frames first
Frequently asked questions
Is double glazing worth it for energy savings?
For single-glazed homes, yes over the long term. Replacing existing double glazing rarely pays back on energy alone.
Is triple glazing better?
Slightly, but the extra cost is rarely recovered in the UK climate.
Do I need building regulations approval?
Use a FENSA or CERTASS registered installer who self-certifies.
Sources and methodology
Energy prices come from the Ofgem price cap for Direct Debit customers (GB average). Installation costs are typical UK ranges from installer quotes and industry guidance, rounded. Savings use today's rates and do not predict future prices.