Extensions & Conversions · Updated 2026
Double glazing cost
Typical range£300–£25,000· Average uPVC double glazed window (supplied & fitted)
Replacement double glazing prices per window for 2025. In the UK, expect to pay between £300 and £25,000, with the typical project around £500 (average upvc double glazed window (supplied & fitted)). Regional variation, specification tier and site access conditions all shift the final quote.
Quick answer: Double glazing cost in the UK typically costs between £300 and £25,000 (Average uPVC double glazed window (supplied & fitted)). London and the South East run 20–35% above this range; the North, Wales and most of Scotland sit 5–15% below.
Homeowners researching this typically also price up front door replacement cost and garage conversion cost. For wider context, browse our bathroom pricing, kitchen pricing and boiler & heating costs.
Cost table
Indicative price ranges (UK, GBP)
| Item | Typical range (GBP) |
|---|---|
uPVC casement window — Per window — most common type, white | £300–£600 |
uPVC sash window — Per window — sliding sash, period style | £600–£1,200 |
Aluminium casement window — Per window — slim frames, contemporary | £600–£1,400 |
Timber casement window — Per window — traditional, needs maintenance | £700–£1,800 |
Full house (10 windows) — All windows replaced, typical 3 bed | £4,000–£15,000 |
Labour costs
Labour typically accounts for 30% of the total project cost in the UK.
Labour line items
| Item | Typical range (GBP) |
|---|---|
Window installation (per window) | £100–£200 |
Scaffold / access (if needed) | £400–£1,200 |
Internal plastering / making good | £50–£150/window |
Disposal of old windows | £30–£80/window |
Materials costs
Materials and fittings make up the remainder of the budget, with specification tier driving most of the variation.
Materials & fittings
| Item | Typical range (GBP) |
|---|---|
uPVC window (standard) | £0–£0 |
Aluminium window | £0–£0 |
Timber window | £0–£0 |
Triple glazing upgrade (per unit) | £0–£0/window |
Georgian bars / decorative | £0–£0/window |
Factors affecting cost in the UK
- ·Region — London and the South East run 15–30% above national averages.
- ·Specification tier — premium materials and finishes can double the base cost.
- ·Access and site conditions — flats, restricted parking and listed buildings add time.
- ·Scope changes mid-project — late design decisions are the biggest cost overrun driver.
- ·Trade availability — quotes rise 10–20% in peak spring and summer months.
Ways to reduce cost
- ·Order a like-for-like swap rather than a re-sized opening.
- ·Choose uPVC over aluminium for a 30–50% price drop at similar U-values.
- ·Book a whole-house package rather than window-by-window orders.
- ·Get three FENSA-registered quotes — biggest national brands rarely win on price.
- ·Time the order for January–March when installers discount to fill diaries.
Frequently asked questions
- How long do double glazed windows last?
- uPVC double glazed units last 20–25 years. The frames typically last longer, but sealed units can fail (showing condensation between the panes) from 15 years onwards. Aluminium frames last 30–45 years; timber, if maintained, can last indefinitely.
- Is triple glazing worth it in the UK?
- Triple glazing adds 15–25% to cost and improves U-values from around 1.2 W/m²K (double) to 0.6–0.8 W/m²K (triple). For most UK homes the payback is very long. It is most beneficial in north-facing rooms, very cold locations, or near-Passivhaus builds.
- Do I need planning permission for new windows?
- Not normally — replacing windows is permitted development. Exceptions: listed buildings (need listed building consent), conservation areas (may need approval for non-like-for-like changes), and flats (may need landlord/freeholder approval).
- What is a FENSA certificate?
- FENSA (Fenestration Self-Assessment Scheme) registered installers self-certify that replacement windows comply with building regulations. You'll receive a certificate which you'll need when selling the property. Always use a FENSA or CERTASS registered installer.
- How much do new windows save on energy bills?
- Replacing single glazing with A-rated double glazing can save £75–£200/year on heating bills. Replacing existing double glazing with newer A++ units saves less — around £20–£50/year per window.