A casement window is hinged at the side or top and opens outward on a handle. It is the default window in most UK homes for good reason: the sash presses tight against the frame seal when closed, so it insulates well, and the simple mechanism keeps it affordable. A fitted uPVC casement costs £400 to £1,000 in 2026, with around £650 typical. You can price your own set in the uPVC window calculator.
How a casement window works
The opening sash is hung on hinges down one side (a side-hung casement) or along the top (a top-hung or awning casement). Turn the handle and the sash swings outward, then the multipoint lock pulls it back hard against a compression seal to close. That compression is why casements seal so well and why they are easy to make weathertight. Fixed (non-opening) casement panes are cheaper still, because they have no mechanism at all.
Nine out of ten houses I fit are casements, and there is a reason for that. The seal is excellent, the cost is sensible, and there is very little to go wrong over twenty-odd years. For most people it is simply the right answer.
Tom Bradley, FENSA-registered installer
Casement window costs in 2026
Material is the main driver. uPVC is the value choice, aluminium adds slim sightlines and durability for a premium, and timber is dearest of all and usually reserved for period or conservation-area homes. The table below is fully fitted, including removal, sealing and the certificate.
| Material | Per window (fitted) | Notes |
|---|---|---|
| uPVC casement | £400–£1,000 | Best value everyday choice |
| Aluminium casement | £540–£1,350 | Slim frames, long life |
| Timber casement | £760–£1,900 | Period and conservation homes |
Source: DGCC 2026 dataset, cross-checked against Checkatrade and StayWarm.
Which homes a casement suits
Best Buy Casements suit the great majority of UK homes: semis, terraces, bungalows, post-war housing and new builds. They give you clean lines, a good seal and a sensible price, which is why they are the standard recommendation here. If your home is modern or has had casements before, this is almost certainly the style to fit.
When a casement is the wrong choice
It depends On a Victorian or Georgian frontage, a casement can look out of place where the street expects vertical sliding sashes, and in a conservation area you may not be allowed to swap a sash for a casement at all. In those cases, read our sash windows guide and check the rules before you buy. On flats and high upper floors where you want to clean the glass from inside, a tilt and turn window may serve you better than a standard casement.
The one job I will not do is fit chunky casements into a row of Victorian terraces with original sashes. It cheapens the whole street, and half the time the conservation officer makes them rip it out anyway. Match the house.
Tom Bradley, FENSA-registered installer
The verdict on casement windows
For most homes, the casement is the best-value, best-sealing, lowest-fuss window you can buy, and uPVC is the sensible default. Save the premium for sash or timber only when the house genuinely calls for it. When you are ready to price the job, the uPVC window calculator turns your window count into a 2026 range in seconds, and if you are weighing styles, our sash windows guide covers the period alternative.
Frequently asked questions
A fitted uPVC casement window costs £400 to £1,000 in 2026, with around £650 typical. Aluminium casements run £540 to £1,350 and timber £760 to £1,900, reflecting the dearer frame materials.
A casement window is hinged at the side or top and opens outward, usually on a handle. It is the most common window style in UK homes, prized for a tight seal and a simple, affordable mechanism.
Yes. Because the sash presses against the frame seal when closed, a modern casement seals tightly and performs well thermally. An A-rated uPVC casement comfortably meets the Part L requirement of a U-value of 1.4 W/m²K or lower.
Casements suit the great majority of modern and post-war UK homes, including semis, terraces, bungalows and new builds. They are less appropriate for Victorian or Georgian period frontages, where sash windows are the traditional style.
Yes. A uPVC casement at £400 to £1,000 is cheaper than a uPVC sash at £700 to £1,500, because the casement mechanism is simpler. For most homes the casement is the better-value choice.
In uPVC or aluminium, almost none beyond an occasional wipe and a drop of oil on the hinges. Timber casements need repainting every 8 to 10 years to protect the frame.