Replacing a sash window in the UK typically costs between £600 and £3,500 per window, fitted. Where you land in that range depends mostly on the material, the glazing, the size of the window and where you live. This guide breaks down 2026 prices so you know what a fair quote looks like.
Quick answer: typical prices per window
These are typical supply-and-fit prices per window, including VAT, for a standard-size sash. London and the South East usually run 20–30% higher.
| Type of window | Typical price per window |
|---|---|
| uPVC sash, double glazed | £600 – £1,200 |
| Softwood timber sash, double glazed | £1,200 – £2,500 |
| Hardwood or Accoya timber sash, double glazed | £1,800 – £3,500 |
| New sashes in your existing frame | Often 30–50% less than a full replacement |
For a typical three-bedroom Victorian terrace with eight sash windows, a full timber replacement often comes to somewhere between £12,000 and £25,000. uPVC is much cheaper, but it is often not allowed on listed buildings or in conservation areas (more on that below).
What affects the cost?
1. Material: timber or uPVC
uPVC sashes are the cheapest option and need little maintenance, but they rarely look exactly like a traditional timber window up close. Timber costs more but looks right on period homes. Within timber, softwood is the most affordable, while hardwood and modified woods such as Accoya last longer and cost more.
2. Glazing
Most replacement sashes are now double glazed. Slim “heritage” double glazing, which keeps the glazing bars thin, costs more than standard units. Vacuum glass is thinner again and performs very well, but it is the most expensive option. Single glazing is usually only used where a listed building requires it.
3. Size and style
Larger windows, arched heads, bay windows and multi-pane Georgian designs (such as six-over-six) all add cost because they take longer to make. Horns, decorative mouldings and special ironmongery add a little more.
4. Box sash or spiral balance
Traditional box sashes use cords, pulleys and hidden weights. Spiral balance windows use springs in the side of the frame instead. Box sashes tend to cost more but are what most period homes originally had.
5. Access and location
Upper-floor windows may need scaffolding, which can add several hundred pounds. Labour costs are higher in London and the South East, and parking or congestion charges may be built into quotes.
6. Planning and consent
If your home is listed, or in a conservation area with an Article 4 direction, you may need consent and detailed joinery drawings before work can start. Some companies prepare these for you, which adds to the cost but saves time. Read our planning guide for the details.
Is repair cheaper than replacement?
Very often, yes. Many old sash windows are made from slow-grown timber that is better quality than most new wood. If the frame is sound, a full overhaul is usually much cheaper than replacing it:
- Replacing cords: around £50–£150 per window
- Draught-proofing: around £150–£450 per window
- Full overhaul (cords, draught-proofing, easing and adjusting): around £350–£750 per window
- Full refurbishment with timber repairs and redecoration: around £650–£1,200 per window
Replacement makes more sense when the frame has extensive rot, the window has been badly altered, or you want a big improvement in energy efficiency that secondary glazing cannot give you. Our guide to sash window repair or replacement walks through the decision.
Ways to keep the cost down
- Get at least three quotes, and make sure each one covers the same thing: removal, disposal, making good, decoration and any scaffolding.
- Ask about new sashes in existing frames. If the box frame is sound, this can save a lot.
- Do all the windows at once. Most firms charge less per window for a larger job.
- Consider secondary glazing if you mainly want warmth and quiet. It typically costs £180–£400 per window and leaves the original sashes untouched.
- Check what is included. A cheap quote that leaves out decorating or making good the plaster can end up costing more.
Paying for a quality job
Look for a company that specialises in sash windows rather than general glazing. Ask to see similar work, check how long they guarantee the joinery, paintwork and glazing units, and confirm whether they can self-certify the work for Building Regulations through a scheme such as FENSA or Certass. See our Building Regulations guide for why this matters when you sell your home.
You can compare sash window companies near you by material, service and product, and see who works on listed buildings.
FAQs
How much does one sash window cost to replace?
A single double-glazed softwood timber sash window typically costs £1,200–£2,500 fitted, and a uPVC sash £600–£1,200. One-off windows can cost a little more per window than a whole-house job.
Are sash windows more expensive in London?
Yes. Expect to pay roughly 20–30% more in London and the South East because of higher labour costs, access and parking.
Do I need planning permission to replace sash windows?
Usually not for a house if the new windows look the same. You may need consent for a listed building, a flat, or a home covered by an Article 4 direction. See our planning guide.
How long do replacement sash windows last?
Well-made timber sashes can last 60 years or more with regular painting. uPVC sashes typically last 20–35 years.
Prices are typical UK figures for 2026 and are a guide only. Always get written quotes for your own windows.
