UPVC replacement costs have shifted again this year, and the gap between a headline quote and a final invoice can be wider than most homeowners expect. This guide sets out realistic 2026 UK prices for the three main UPVC window styles, what actually drives the number on your quote, and the extras that quietly appear later. Read it before you sign anything.
What a single UPVC window costs in 2026
The unit price of a UPVC window depends on style, size, glazing spec and how easy it is to fit. A standard casement in a ground-floor bedroom is a very different job from a first-floor bay above a public pavement, even if the frames themselves are similar. As a broad guide for a fully fitted single window in 2026, you should expect the following ranges.
A standard casement of around 1,000 by 1,200 mm sits between £450 and £900 fitted. This is the most common style, the cheapest to make and the fastest to fit. A tilt-and-turn window in the same size runs £650 to £1,300 because the hardware is heavier and the mechanism dual-mode. A flush UPVC sash, the timber-look profile popular on period homes, sits at £750 to £1,400. A vertical slider sash in UPVC, mimicking a traditional box sash, is £900 to £2,400 because the mechanism is more complex. A bay window in a three or four light configuration is £1,600 to £3,800 including a bay pole where needed. A pair of UPVC french doors is £1,300 to £3,200, and the cost rises fast with sidelights or wider openings.
These prices assume A rated double glazing, standard white foil, FENSA or CERTASS registered installation and no significant remedial work. Anything outside those assumptions moves the price, sometimes considerably.
Full-house UPVC replacement pricing by house type
Whole-property replacements are usually where the biggest savings and the biggest surprises live. Suppliers price per window when quoting, but a full package almost always attracts a project discount of five to fifteen per cent. In 2026, a typical UK homeowner is paying the following for an eight-to-twelve-window UPVC replacement.
| Property type | Typical windows | Full-house UPVC 2026 |
|---|---|---|
| Two-bed mid terrace | 5 to 7 | £3,200 to £5,400 |
| Three-bed semi-detached | 7 to 10 | £4,500 to £7,500 |
| Four-bed detached | 10 to 14 | £6,500 to £9,500 |
| Larger detached with bays or bi-folds | 14 or more | £8,500 to £14,000+ |
If a quote sits far below these ranges for your house size, the specification is almost certainly thinner than a properly performing 2026 window should be, or the fitting scope excludes something essential like making good the plaster reveal.
What actually drives the price of a UPVC window
Two windows that look identical on a brochure can sit £300 apart per unit, and the reasons are rarely obvious in the showroom. When we match homeowners with installers we see the same six drivers again and again.
Frame chamber count
Modern UPVC frames use internal chambers to trap air and improve thermal performance. A basic 3 to 5 chamber system is fine for many replacements, but 6 to 7 chamber frames are now standard on premium ranges and are typically required to hit the tightest U-values without paying for triple glazing.
Glazing rating and gas fill
An A+ Window Energy Rating is now the entry point for a serious replacement. Argon fill is standard, low-emissivity soft coats are near-universal, and warm-edge spacers should be too. Krypton fill and triple glazing push the price up by ten to twenty-five per cent per window.
Hardware and security
Yale, Roto, Maco and Siegenia multipoint locks and hinges cost more than unbranded equivalents, but they are what allows an installer to certify to PAS 24. Espagnolette handles, key-locking on ground-floor units and restrictor stays are all small adders that add up.
Colour and foil finish
White UPVC is the base price. Anthracite grey inside and out will usually add £40 to £90 per window. Woodgrain foils (Rosewood, Golden Oak, Irish Oak) sit similarly, and dual-colour (white inside, coloured outside) is more expensive again because the frame is co-extruded.
Trickle vents
Since Building Regulations Part F was updated alongside Part L in 2021, background ventilation is required on almost every replacement. Trickle vents in the head of each frame add £15 to £35 per window and are non-negotiable unless the property already has adequate ventilation elsewhere.
Access and fitting complexity
Upper-floor bays, windows over conservatory roofs, coastal exposure requiring scaffold and windows above public pavements all attract labour premiums. On a large detached this can add £500 to £1,500 to the overall project.
The hidden extras that appear late
The most common complaint in the UK glazing market is not price itself, it is unexpected extras. The five below are the ones we see most often on final invoices where they were absent from the original quote.
- Bay poles or structural supports for load-bearing bays, £150 to £400 per bay
- Lintel repair or replacement where corroded steel is discovered, £250 to £600 per opening
- Plaster reinstatement on internal reveals, £40 to £120 per window
- External sill replacement where the existing sill is rotten or too shallow, £60 to £150 per window
- Cill nose extensions, cloaking trims or box sash bottom-rail cladding to hide a legacy detail, £30 to £90 per window
Ask specifically whether each of these is included, excluded or provisional. A quote that says “making good included” without listing what “good” covers is not a firm price.
FENSA and CERTASS certification, and why it matters to the bill
Every replacement window in England and Wales must be notified to Building Control. The two dominant self-certification schemes are FENSA and CERTASS. Membership fees and per-notification levies are baked into the installer’s rates, typically £15 to £35 per window depending on scheme and volume. If a quote is materially cheaper than the market and the installer is not on either register, the notification cost falls to you (£150 to £300 through Local Authority Building Control), and you will need a Regularisation Certificate later if you skip the step. That certificate can hold up conveyancing on sale.
Quote checklist: six things every UPVC quote should show
Before you sign, work down this list and confirm each item is written on the paperwork rather than promised verbally.
- The Uw whole-window U-value in W/m²K (should be 1.4 or lower to meet Part L 2021)
- The Window Energy Rating (A or A+ as a minimum for 2026)
- Trickle vent specification and location on each window
- Named hardware brand and PAS 24 compliance for ground-floor units
- Scheme membership number (FENSA or CERTASS) and the guarantee-backed insurance provider
- A written scope for making good, including plaster, sills, lintels and external decoration
If a salesperson resists putting any of these in writing, that is signal in itself.
When to get more than one quote (and how many)
The UPVC market is quote-sensitive. Three quotes from three different installers on the same specification will typically span 25 to 40 per cent on price, even excluding the outliers. Two is not enough to see the shape of the market. Four is usually enough to spot both the underpriced quote (which is often underspecified) and the premium quote (which is often no better than the middle one, just marketed harder).
When you compare, match the specification line-by-line rather than the total. A £6,200 quote with 7-chamber frames, A+ glass, warm-edge spacers and full plaster making-good is not directly comparable with a £5,400 quote using 5-chamber frames, A-rated glass and no reveal repair. In our matching data, the median UK homeowner saves £900 to £1,600 on a full-house replacement by putting three like-for-like specifications in front of vetted installers, and a further £200 to £500 by timing the order for the slower months of January, February or August.
How payment terms should look
Deposits above 25 per cent are a warning sign, and any deposit paid should be protected by an insurance-backed guarantee that is separately confirmed in writing. Staged payments tied to survey, manufacture and completion are normal on larger jobs. Full payment on the day of fitting, before you have had the chance to inspect the work in daylight, is not.
What to do next
Compare 3 vetted installer quotes at legacywindows.co.uk/quote/ — takes 60 seconds and there’s no obligation.