Casement windows are side-hinged windows that open outwards, and they remain the UK's most popular window style in 2026, typically costing £300 to £850 per window fitted. This guide compares the three main types, flush, uPVC and French casements, with typical prices for each, and shows how to check your funding options in 60 seconds.
Windows need to be replaced every 15 to 20 years to keep working as they should. If you have noticed draughts, condensation or frost on the inside of your home, or a change in your windows' appearance such as damaged, broken or warped frames, that is a clear sign they have reached the end of their life.
Other good reasons to replace your windows include cutting energy bills and making your home more appealing to potential buyers if you are thinking of selling. Whichever applies to you, this guide will help you decide which type of casement window to install.
Why choose casement windows?
More than 20 different window styles can be installed in a UK home, including bay windows, double-hung windows and awning windows. Each offers something different in benefits and looks. So why pick casement windows?
Casement windows sit in the lower price bracket, typically £300 to £850 per window fitted as a 2026 guide, but the quality does not suffer for it. On top of the attractive price, they look stylish with their slimline frames, need little to no maintenance, reduce outside noise, and stand firm against even the stormiest weather.
How do casement windows open?
One of the biggest reasons people choose casement windows is the way they open. They are usually hinged at the side and open outwards, either left to right or right to left.
You can choose which side the hinge sits on to suit your room and your dominant hand, so the handle is always easy to reach. You can also have the sash hinged at the top instead, creating an awning-style opening that lets you ventilate the room even in light rain.
What types of casement windows are there?
There are three main types of casement window to choose from:
- Flush casement windows
- uPVC casement windows
- French casement windows
Here are typical 2026 guide prices for each, followed by the detail on every type:
| Casement window type | Typical 2026 guide price |
|---|---|
| Standard uPVC casement (fully fitted, per window) | £240 to £600 |
| Casement windows overall (per window, fitted) | £300 to £850 |
| Flush aluminium casement (per window, supply) | £180 to £540 |
| French casement (per window, fitted) | £520 to £880 |
| Whole house, 3-bed (uPVC casements throughout) | £5,200 to £5,800 |
Could you qualify for funding towards new windows and doors? Homeowners with windows five years old or older can check in under 60 seconds. Launch the funding checker.
Flush casement windows
Casement windows have been around for nearly two centuries, becoming the popular choice for Georgian, Victorian and Edwardian properties throughout the UK. Those windows gave period homes their distinct look, character and heritage, something many owners are afraid to lose when replacing windows.
You do not have to choose between character and comfort. Flush casement windows mimic the traditional look, where the sash sits flush with the frame, while modern double glazing improves insulation dramatically. That means lower energy bills, which is good for your wallet and the environment.
You will notice the benefits as soon as flush casements are installed: rooms flood with natural light, and the brighter atmosphere transforms how the space feels.
What material can you choose?
Timber was the popular choice in the 19th century, but modern frame materials cope far better with harsh weather and general wear. Flush casement frames now come in two main materials: uPVC and aluminium.
Flush casement aluminium windows
Flush casement aluminium windows are increasingly popular for their sleek, modern aesthetics, combining durability with energy efficiency. The sash sits flush with the frame for a clean, streamlined look that suits both contemporary and traditional properties.
The strength of aluminium allows larger windows with slimmer frames, maximising natural light and views. The material is renowned for low maintenance: it resists warping, rotting and fading, and needs nothing more than simple cleaning.
Thermal breaks in the frames significantly reduce heat transfer, which can lower energy bills and keep rooms more comfortable. Add the versatility in design and colour options, and flush aluminium casements are a top choice for enhancing a property's looks.
As a typical 2026 guide, flush casement aluminium windows range from £180 to £540 per window depending on size and colour, before fitting.
Flush uPVC casement windows
uPVC flush casement frames offer excellent security thanks to the robust nature of the material. Combined with double or triple glazing, they deter break-ins and reduce noise levels.
They are also low maintenance, which saves you money over the long term. The frames stay looking as fresh as the day they were fitted, ideal for coastal homes that face harsh weather regularly.
Just as with aluminium frames, you can add a personal touch with different colours and finishes, though non-standard options increase the price.
uPVC casement windows
Standard uPVC casement windows are the most popular choice for UK homeowners thanks to the light they let in, the added security and their long life. They are also quick to install; our window fitters guide explains what to expect on installation day.
Price-wise they are the most cost-effective casement option, costing around £240 up to about £600 per window fully fitted as a 2026 guide. Fitting a whole three-bedroom house with new uPVC casements typically costs between £5,200 and £5,800; see our full uPVC window cost guide for a detailed breakdown.
Because of the material it is made from, uPVC is unlikely to discolour over time. It is lightweight yet durable, resists weathering and holds its shape, all of which makes it an even more cost-effective option.
French casement windows
French casement windows work like French doors: two sashes open side by side to create one large opening with no vertical post between them. Both windows open at the same time, giving completely uninterrupted views.
They work best where you need two windows next to each other, such as a bedroom or kitchen, and the wide clear opening can double as an emergency escape route in upstairs rooms.
Fully open, a French casement floods the room with light and improves airflow; closed, it keeps the heat contained. As a typical 2026 guide you will pay between £520 and £880 per window, which makes it the most expensive casement option, but if you want to make the most of the outdoors on your terms, it is the best option by far.
Funding towards new casement windows
If your windows are five years old or older, you may qualify for grants or funding towards replacements. It takes under a minute to check and there is no obligation.
The Help 2 Buy Windows grant has nothing to do with the UK government; it is funded 100% by Help 2 Buy Windows through the sale of leads to our clients.
Frequently asked questions
How much do casement windows cost in 2026?
As a typical 2026 guide, casement windows cost between £300 and £850 per window fitted. Standard uPVC casements sit at the lower end at around £240 to £600 fully fitted, French casements at the upper end at around £520 to £880, and flush aluminium frames from around £180 to £540 per window before fitting, depending on size and colour.
What is a flush casement window?
A flush casement window has a sash that sits flush with the frame when closed, rather than standing slightly proud of it. The style mimics traditional Georgian, Victorian and Edwardian timber windows, so it suits period properties, while modern uPVC and aluminium versions add double glazing performance.
Should I choose uPVC or aluminium casement windows?
uPVC is the most cost-effective choice, is secure and low maintenance, and comes in a wide range of colours and woodgrain finishes. Aluminium offers slimmer frames, larger glass areas and a sleek modern look with excellent durability, but it usually costs more. Both perform well thermally when fitted with modern double glazing.
What is a French casement window?
A French casement window has two sashes that open outwards side by side with no fixed vertical post between them, creating one large unobstructed opening. They maximise light and airflow, can serve as a fire escape route, and typically cost around £520 to £880 per window as a 2026 guide.
How often should windows be replaced?
Windows generally need replacing every 15 to 20 years to keep performing as they should. Draughts, condensation, frost forming on the inside, and damaged or warped frames are all signs that your windows have reached the end of their life.