Windows
Casement windows
A casement window is hinged at the side or top and opens outwards. It is the most common window style in the UK, works in uPVC, aluminium and timber, and is usually the cheapest style to replace because it is the simplest to make and fit.
Casement is a style rather than a material, so most of your cost decision happens elsewhere. What the style determines is how the window opens, how easily you can clean it, and whether it can double as a fire escape.
Indicative guide, not a quote
per window, supplied and fitted
£400 – £850
These figures come from published industry price guides, not official statistics, and several of those sources are installers or comparison sites with a commercial interest. They are a starting point for a conversation, not a quote. Your installer sets the actual price after measuring.
Costwise UK new windows cost guide · checked 2026-10-09
Side-hung, top-hung, and why it matters
A side-hung casement is hinged on the left or right and swings open like a door. A top-hung casement, sometimes called an awning, is hinged along the top and pushes outwards from the bottom, which lets you leave it slightly open in rain.
Most windows combine both: a large side-hung opener for ventilation and escape, with a top-hung vent above. The fixed panes between them are the cheapest part of the window, which is why a window with fewer openers costs less.
Egress and fire escape
Building regulations require an escape window in habitable rooms above ground floor level in many situations, with a minimum clear opening. If you are replacing a window that currently serves as a means of escape, the replacement must still do so.
This catches people out when they reduce the number of openers to save money. Raise it with your installer at survey stage rather than discovering it at sign-off.
Flush or stormproof
A stormproof casement has a lipped sash that sits proud of the frame. It is the standard, cheaper option and sheds water well. A flush casement sits level with the frame for a cleaner, more traditional line, and costs more.
Casement windows: common questions
- Are casement windows secure?
- Modern casements use multi-point locking and should be tested to PAS 24. Ask whether the windows you are quoted are PAS 24 certified, since some insurers and most new-build specifications expect it.
- Which way should a casement open?
- Consider the path outside, the prevailing wind, and how you will clean it. Hinging away from a footpath avoids an opener swinging into people, and easy-clean hinges let you reach the outer face from inside.
- Do I need an opener in every window?
- No, and fixed panes are cheaper. Each habitable room does need adequate ventilation, and rooms requiring a means of escape need a compliant opener, so the layout is a decision to make at survey.
Other windows
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uPVC windows
£400 – £850 fitted
uPVC windows cost £400 to £850 fitted. What separates a good one from a cheap one, what the regulations require, and when uPVC is the wrong choice.
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Aluminium windows
£600 – £1,250 fitted
Aluminium windows cost £600 to £1,250 fitted. Why the slim sightlines matter, what a thermal break does, and whether the extra over uPVC is worth it.
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Timber windows
£800 – £1,600 fitted
Timber windows cost £800 to £1,600 fitted. Why modern engineered timber is not the wood you remember, the real maintenance, and when it is compulsory.
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Sash windows
£800 – £1,800 fitted
Sash windows cost £800 to £1,800 fitted. Cords and weights versus spiral balances, when repair beats replacement, and fitting double glazing.
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Tilt and turn windows
£400 – £850 fitted
Tilt and turn windows open two ways: a secure vent, or fully inwards for cleaning and escape. Why flats and upper floors usually choose them.
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Bay and bow windows
£1,500 – £3,000 fitted
Bay and bow windows cost £1,500 to £3,000 fitted because many carry structural load. The difference between them and what a survey must check.
TrustedGlazing does not make, supply or fit windows and doors, and the prices above are published industry guides rather than our own. We match your enquiry to one vetted local installer, who quotes and contracts with you directly.