A new double glazed sash window costs £600 to £1,500 fitted in uPVC and £1,330 to £2,850 in timber in 2026. A three-bed house with five or six uPVC sashes comes to £2,500 to £4,800. If you would rather keep your frames, double glazing the existing sashes costs £650 to £1,300 a window. Price yours in a minute, then get free quotes from local installers.
Double glazed sash window prices by material
These are fitted prices per window for a new double glazed sash. A uPVC sash comes double glazed as standard: Checkatrade lists "argon-filled units as standard on most suppliers" in a normal uPVC sash quote, and says uPVC double glazed sash windows start around £700.
| Material | Fitted price per window | Typical |
|---|---|---|
| uPVC sash | £600 to £1,500 | £1,050 |
| Aluminium sash | £950 to £2,030 | – |
| Timber sash (heritage) | £1,330 to £2,850 | £1,950 |
DGCC 2026 price table, cross-checked against Checkatrade (June 2026), ExpertSure (August 2026) and FMB Home Picks (September 2026). The top of the uPVC range is for large, woodgrain or heritage-spec sashes; the dated guides stop at £1,200 for a standard size.
A uPVC sash is the value choice wherever planning allows it, at roughly half the price of timber and with no repainting. The sash window price calculator breaks the uPVC figure down by source and size, and prices your own windows.
Double glazed timber sash windows
Timber costs more because each sash is joinery, and the guides spread widely on how much more. Softwood sits at the bottom of every range and hardwood at the top.
| Source (date) | What is priced | Fitted price |
|---|---|---|
| Site benchmark (2026) | Timber heritage sash | £1,330 to £2,850 |
| Checkatrade (June 2026) | Timber sash, general range | £1,000 to £3,000 |
| Checkatrade (June 2026) | 600 x 900 mm and 1,200 x 1,200 mm | £1,400 to £1,800 |
| ExpertSure (August 2026) | Softwood / hardwood, 600 x 1,200 mm | £1,200 to £2,500 / £1,800 to £3,500 |
| FMB Home Picks (September 2026) | 600 x 900 mm and 900 x 1,200 mm | £2,450 and £2,775 |
FMB Home Picks carries an affiliate disclosure and describes its method as desk research and mystery shopping. Sources as recorded in lib/research/upvc-sash-cost-2026.md.
A well-kept timber sash lasts far longer than uPVC, but it needs repainting every 5 to 8 years. On a listed building, timber is usually the only material you will be allowed, so check before comparing quotes.
What a whole house of sash windows costs
Checkatrade budgets £2,500 to £4,800 for a typical three-bedroom house with five or six uPVC sashes (June 2026). ExpertSure puts a three-bed Victorian terrace with six windows at £4,500 to £21,000, from uPVC at the bottom to hardwood at the top. In like-for-like timber, a full Victorian terrace of twelve windows runs to £18,000 to £30,000, a figure from one London sash firm; our Victorian terrace cost guide covers that job in full.
Scaffolding for upper floors, repairs to lintels or reveals, and redecorating are usually extra on top of every figure here.
Keeping your frames: double glaze the existing sashes
You do not always need a new window. Checkatrade (July 2026) puts fitting double glazing into existing sash frames at £650 to £1,300 a window. It does not say whether that means slim units, so read our guide to slimline double glazing before you ask for a price.
On a listed building, replacing a window always needs consent, and new glass in the old sashes is likely to as well. Secondary glazing, at £300 to £500 for a standard window, keeps the original sash untouched; see the secondary glazing cost guide and our listed building window costs.
Sash window prices in London
Checkatrade says rates in London and the South East tend to run higher than the national average. Applying the sitewide London adjustment of +20% to the uPVC range gives about £720 to £1,800 per sash, fitted. Many London streets are conservation areas, where an Article 4 direction can rule out uPVC; the London double glazing costs page and our guide to conservation area window costs cover both.
What moves a sash quote up or down
- Balances. uPVC sashes run on spring balances as standard. Traditional cords and weights cost more: ExpertSure puts them at 20 to 40% above a spring balance sash, and one London firm at £200 to £400 a window.
- Finish. ExpertSure adds £200 to £500 for a colour or woodgrain finish on uPVC.
- Style. A sash costs about 50% more than a casement of the same size, which is why the casement vs sash comparison is worth a look on a non-period house.
- Planning. A listed building or an Article 4 direction can decide the material for you.
For the parts of a box sash and how each balance works, see sash windows explained.
Get free quotes for double glazed sash windows
Tell us about your windows and we pass your details to local installers covering your area, who will contact you to arrange a survey. Say if the house is listed or in a conservation area.
Questions before you book
How much do double glazed sash windows cost?
A new uPVC sash window costs £600 to £1,500 fully fitted in 2026, and Checkatrade lists argon-filled double glazing as standard in that price. A timber sash runs £1,330 to £2,850 a window, and an aluminium sash £950 to £2,030. For a three-bed house with five or six uPVC sashes, Checkatrade budgets £2,500 to £4,800.
How much are double glazed wooden sash windows?
Our range for a timber heritage sash is £1,330 to £2,850 fitted, typically around £1,950. The cost guides spread wider: Checkatrade gives £1,000 to £3,000, with softwood at the bottom and hardwood such as oak or Accoya at the top, and ExpertSure gives £1,200 to £2,500 for softwood and £1,800 to £3,500 for hardwood.
Can I double glaze my existing sash windows instead?
Often, yes. Checkatrade (July 2026) puts fitting double glazing into existing sash frames at £650 to £1,300 a window, though it does not say whether the units are slim. On a listed building this usually needs consent, and secondary glazing at £300 to £500 a standard window (Checkatrade, July 2026) is the route that keeps the original glass.
Are sash windows more expensive in London?
Yes. Checkatrade says rates in London and the South East tend to run higher than the national average. Our modelled London figure, 20% above the UK average, puts a uPVC sash at £720 to £1,800 fitted, and many London streets are conservation areas where timber may be required.