What do sash windows cost?
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Sash against casement, by number of windows
| Windows | Sliding sash, inc VAT | Casement, inc VAT |
|---|---|---|
| 4 | £6,293 – £11,442 | £4,197 – £7,630 |
| 6 | £9,027 – £16,413 | £5,883 – £10,696 |
| 8 | £11,762 – £21,386 | £7,570 – £13,763 |
| 10 | £14,496 – £26,357 | £9,256 – £16,829 |
Why a sash costs more
A sliding sash is two frames that move inside a box, with balances to hold them where you leave them. There is more to make and more to fit than a casement that hinges open, and it shows in the price: a sash is roughly two-thirds more than a casement of the same size.
These figures are for replacement sash windows. Restoring or draught-proofing original timber sashes is a different trade with its own prices, and nothing on this page covers it. If your house is listed or in a conservation area, check with the council before replacing them at all.
What is included in these prices
Supplying and fitting the new windows, taking out and taking away the old ones, and sealing and making good around each new frame. VAT is in every figure.
Access for upstairs windows is included where the estimate needs it (£936 for a tower), and small jobs carry a minimum charge of £1,140. Not included: new sills or lintels where the old ones have failed, internal decorating, and anything structural.
Planning estimate or quotation?
Every figure on this page is a planning estimate: what a job like this typically costs, for budgeting and for judging the quotes you get. It is not a quotation. A quotation comes from an installer after a survey, when the exact sizes, specification and condition of your house are known.
Facet Pro narrows the estimate to your own house from a photograph of the front — the windows it can see, the wall it can measure against your front door — and says which parts are measured and which are estimated for your house type. Your installer confirms the figure on survey.
Facet Pro is in beta. Our measurement of wall area from a photograph is still being calibrated against surveyed properties, so treat wall and roof figures as indicative and window figures as a guide.
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These are planning estimates — not a quotation, and not a survey. Windows and doors: what these jobs actually sell for, from 24 years of selling them, checked against current UK prices. Walls, roof and roofline: UK material and labour rates, with scaffolding, waste and VAT. What you pay depends on your own house and, more than anything else, on which company quotes it. Your installer confirms the figure on survey.