The short answer: a single A-rated uPVC casement window costs around £650 fitted in 2026, within a working range of £400 to £1,000 per window. That figure covers supply, labour, removing the old window, sealing the new one and the FENSA certificate. The number moves with the style, the frame material and where you live. You can put your own count and spec into the uPVC window calculator to turn this per-window rate into a whole-house range.
The headline number, explained
When people ask what double glazing costs, they almost always mean a standard casement window, because that is the most common style in UK homes. For 2026, our cross-checked figure for a fitted A-rated uPVC casement is around £650, sitting inside a £400 to £1,000 band. The low end is a small, simple ground-floor window from a competitive local fitter. The high end is a larger window, an upper floor needing access equipment, or a premium glass specification. If you want the full whole-house picture rather than a single window, the cost-by-style breakdown sets each style and material side by side.
If a salesperson quotes you £1,400 for a bog-standard ground-floor uPVC casement, walk away. That is roughly double the going rate, and the "discount" they offer next will only bring it back to where it should have started.
Tom Bradley, FENSA-registered installer
Cost per window by style
Style is the second biggest lever after frame material. A casement is a simple hinged window, so it is the cheapest opening style. Sash windows slide vertically and carry more mechanism, so they cost more. Bay windows are effectively several windows in one structural opening, which is why they run into four figures even in uPVC.
| Style | uPVC | Aluminium | Timber |
|---|---|---|---|
| Casement | £400–£1,000 | £540–£1,350 | £760–£1,900 |
| Sash | £700–£1,500 | £950–£2,030 | £1,330–£2,850 |
| Tilt & Turn | £500–£1,200 | £680–£1,620 | £950–£2,280 |
| Bay (per bay) | £1,100–£3,000 | £1,490–£4,050 | £2,090–£5,700 |
| Fixed | £220–£440 | £300–£590 | £420–£840 |
| French Doors | £1,100–£2,200 | £1,490–£2,970 | £2,090–£4,180 |
| Bifold Doors | £2,200–£5,500 | £2,970–£7,430 | £4,180–£10,450 |
Source: DGCC 2026 dataset, cross-checked against Checkatrade and StayWarm. The casement row is the best-value everyday choice.
Cost per window by frame material
Material is the single biggest driver of the per-window price. uPVC is the baseline. Aluminium costs more for its slim sightlines and long life, and timber costs more again for its looks and its suitability in period homes. If you are weighing the slim-frame look against the saving, our uPVC versus aluminium comparison sets out where each one earns its keep.
| Material | Per window (fitted) | Best for |
|---|---|---|
| uPVC | £400–£1,000 | Best value, low maintenance, excellent insulation |
| Aluminium | £540–£1,350 | Slim frames, modern look, very durable |
| Timber | £760–£1,900 | Period and listed properties, premium finish |
Source: DGCC 2026 dataset. Aluminium is roughly 30 to 40% above uPVC; timber is 60 to 110% above.
Material is where the money goes. Two identical-looking casements can be £600 apart purely on frame choice. Pick uPVC unless the look genuinely matters or your conservation officer insists on timber.
Tom Bradley, FENSA-registered installer
What pushes your per-window price up or down
Beyond style and material, four things move the figure within its range. Size matters, because a large pane costs more glass and more labour to lift. Access matters, because an upper floor needing scaffolding adds a fixed cost shared across the job. Glass specification matters, with toughened, acoustic or triple-glazed units costing more. And location matters: prices in London and the South East run 15 to 25% above the UK average. Doing the whole house in one visit usually lowers the per-window rate, because the installer spreads the call-out, removal and certificate costs across more units.
How to use the per-window figure
Treat £650 as a sanity check, not a quote. Multiply it by your window count for a rough whole-house figure, then adjust up for sash or bay styles, dearer materials and a pricier region. When the written quotes come in, any window priced far above the range in the tables above deserves a question. If a quote feels high or the sales approach feels pushy, read how to avoid being overcharged before you sign anything.
Frequently asked questions
Expect to pay around £650 fitted for a typical A-rated uPVC casement window in 2026, within a working range of £400 to £1,000. Larger styles such as sash and bay windows cost more, and aluminium or timber frames push the figure higher again.
Per-window prices vary with the style, the frame material, the size of the opening, access (upper floors and scaffolding cost more) and your region. London and the South East are typically 15 to 25% dearer than the UK average.
Usually yes. Installers spread their fixed costs (the visit, the removal, the certificate) across the job, so the per-window rate often falls when you order a full set rather than one or two windows.
The figures on this page are fully fitted, which covers supply, labour, removal of the old window, sealing and the FENSA certificate. Always confirm whether a written quote is supply-only or fully fitted, and whether VAT is included.
A uPVC sash window typically runs £700 to £1,500 fitted, against £400 to £1,000 for a uPVC casement. Timber sash windows for period homes cost more still.
A fixed (non-opening) uPVC window is the cheapest at £220 to £440, because it has no moving parts. Among opening windows, the uPVC casement is the most affordable everyday choice.