The Independent’s journalism is supported by our readers. When you purchase through links on our site, we may earn commission. Why trust us?
Casement windows are among the most popular types of windows in the UK. Operating via a handle and swinging open like a door, casement windows are straightforward to use and come in diverse styles.
Casement windows suit all properties, including modern new-builds and period homes, and their wide popularity means they’re among the most affordable of any window type.
This comprehensive guide to casement windows explains everything you need to know, including materials, glazing, window prices, and what to consider before searching for quotes.
Complete our short form to request windows quotes for your home
Get free, no obligation quotes from up to 5 local windows installers
Compare quotes and pick the option that best suits your needs
Casement windows are ubiquitous throughout the UK. They run on side hinges and open outwards like a door. The literal meaning of “casement” is a window with a side hinge.
A casement window’s hinged design enables an unobstructed view and excellent ventilation as the entirety of the window opens, unlike sliding or sash windows, which only partially open.
There are many casement window types, including compact singles, doubles and triples. Larger double and triple casement windows often have smaller top windows and fixed panels in the middle.
Casement window frames can be constructed from unplasticised polyvinyl chloride (uPVC), wood, aluminium, composite or other materials, and glazing ranges from single- and double-glazed to triple-glazed and low-emissivity (low-E) glass.
Casement windows suit practically all properties and window apertures (the space in the wall that the window slots in), making them somewhat of a jack-of-all-trades among window styles.
The casement window mechanism is relatively straightforward. When you turn the handle and push the window outwards, the window swings out, letting fresh air into the property.
Another common feature of casement windows is the window stay, a metal bar that holds the open window in place to prevent it from being blown by the wind. For more basic casement windows, you manually hook the stay into place.
This simple design enables the window to capture even mild breezes as the opened window funnels air into the home.
When closed, casement windows press firmly against the frame, creating an airtight seal that prevents drafts. This also makes them harder to force inwards.
Casement windows are secure, as the lock is embedded into the frame. Larger casement windows feature multiple locks across the length of the frame, also called multipoint locking systems.
So, when you turn the key in the lock, it operates multiple bolts rather than just one.
There are a few types of casement windows. Here are the four main types you might come across:
Single casement windows are designed for standard-sized window frames; they’re simple and no-nonsense windows for standard-sized apertures.
Also referred to as “French windows,” they consist of two sashes that swing open from the centre, similar to French doors.
They offer wide, unrestricted views since they have no central style (the spine running between window frames).
Most modern casement windows are push-out, meaning you simply push them out to open them up.
Some use a crankshaft that you can wind to operate the window, but these are fairly uncommon in the UK. You might see some casement windows explicitly listed as “push-out.”
Large bow and bay windows, typically constructed from three or more connected window panels, often consist of casement windows.
One casement window subtype you’ll possibly encounter is the flush casement window.
Flush casement windows sit flush with the frame, smoothing the window’s external appearance, unlike typical casement windows where the window often protrudes from the frame.
Besides their smoother exterior aesthetic and higher cost, flush casement windows are the same as standard ones. Like standard casement windows, flush variants hinge at the side and can open wide for optimal ventilation.
Most modern casement windows are quite low profile anyway, but it’s still worth being aware of this casement window subtype.
Casement windows are constructed from all major window frame materials, including uPVC, wood, aluminium and composite.
Let’s explore the most commonly used materials for casement windows.
Timber or wooden window frames are a classic choice, providing a natural beauty difficult to replicate with synthetic materials. Several wood types are used for windows, including pine, fir, oak and mahogany.
Engineered or layered wood, which uses bonded layers of wood to create uniformly built frames with natural grains, is a modern alternative to solid wood.
Moreover, wood is an excellent natural insulator, ensuring interior temperature stability and minimal heat loss. Wooden windows are also highly durable if well maintained, often lasting for several decades, particularly in the case of oak.
However, wooden windows demand regular maintenance. They must be periodically treated with paint or a wood preservative to protect them from rot, pests and weather-induced decay.
Wooden casement windows offer superb natural aesthetics and technical performance despite additional maintenance demands.
uPVC is likely the most popular window frame construction material. It offers affordability, excellent energy efficiency and low maintenance requirements.
uPVC windows don’t warp, rot or rust and only require occasional cleaning with soapy water to keep them looking as good as new.
Regarding thermal performance, uPVC windows offer impressive insulation, helping maintain a comfortable indoor temperature and reduce energy costs. They’re also available in various colours and finishes, including wood grain effects.
As a plastic, you might suspect uPVC is bad for the environment, but it can be recycled up to 10 times, making it one of the most widely recycled synthetic materials.
Aluminium windows are strong and durable with sleek, contemporary aesthetics.
They’re virtually maintenance-free and feature slim window frames, maximising the glass area for excellent views and plenty of natural light.
As a window frame material, aluminium is also highly durable, resistant to rust and capable of withstanding harsh weather. Its maintenance needs are minimal, with only routine cleaning necessary to keep them in tip-top shape.
However, aluminium is a metal and conducts heat, making aluminium windows less energy efficient than timber or uPVC windows.
To overcome this, modern aluminium windows come with a thermal break, a barrier within the frame that reduces heat transfer, enhancing their insulative properties.
Aluminium casement windows blend a sleek, modern aesthetic with superb technical performance.
Composite casement windows combine two or more materials, usually timber and aluminium, to create a high-performance window with rock-solid technical characteristics.
The outer layer is often made of aluminium for durability and minimal maintenance, while the interior layer is typically timber, providing excellent insulation and a pleasing aesthetic. The result is a great window with solid energy efficiency that requires little maintenance.
Despite their advantages, composite windows often cost more than uPVC and aluminium windows. Composite casement windows offer a middle ground between modern and traditional materials.
Casement windows come in many different finishes to match your property.
Here, we’ll explore common finishes for uPVC, aluminium, wood and composite casement windows.
Though we often imagine uPVC as plain white, modern uPVC windows come in various finishes.
Aluminium windows are available in multiple colours and can be painted or sprayed.
Wooden windows offer a timeless appeal and excellent insulative properties. They look great as they are or when finished with stain or varnish.
Composite windows combine the strengths of two materials, often uPVC or aluminium on the outside for weather resistance and wood on the inside for a warm aesthetic.
Now let’s turn our attention to different casement window glazing options.
Casement windows can be paired with any typical glazing, including double, triple and low-E glass.
Here’s an overview of casement window glazing.
Double-glazed windows, comprising two panes of glass separated by an inert gas-filled space, have become the benchmark in the UK.
As of April 2002, building regulations effectively banned single glazing for new window installations.
Double glazing typically achieves a British Fenestration Rating Council (BFRC) Window Energy Rating of A or above, making it a solid choice for reducing heat loss and energy bills. Double-glazed windows also offer excellent sound insulation and enhanced security compared to their single-glazed counterparts.
Triple-glazed windows feature three glass panes, each separated by an inert gas-filled cavity.
This design further slows the heat transfer rate, making triple-glazed windows even more energy efficient than double-glazed ones.
With the additional insulation layer, triple-glazed windows often achieve BFRC ratings of A+ or higher, making them ideal for homeowners seeking the utmost energy efficiency. The dual gas-filled cavities offer superior resistance to heat transfer.
The noise reduction offered by triple-glazed windows is also top-tier thanks to the additional glass pane and insulating space. Triple glazing can provide a noticeably quieter environment for homes in high-traffic areas or bustling neighbourhoods.
If you’re looking for high-end glazing that delivers exceptional technical performance, opt for triple glazing. Some upfront costs are recovered by reductions in energy bills, especially when coupled with high-quality insulative window frames.
Low-E glass has a microscopically thin, transparent coating, reflecting heat into the room while allowing natural light to enter. It dramatically improves the energy efficiency of windows, especially when used with double or triple glazing.
In a typical low-E window, the coated pane faces the inside of the house, reflecting heat into the room and preventing it from escaping outside. This means that your heating system works less to maintain a comfortable temperature during the colder months, reducing energy costs.
Additionally, low-E glass can prevent a considerable amount of the sun’s heat from entering the home during warmer months, helping keep your home cool.
Low-E coatings can be combined with either double glazing or triple glazing. Low-E triple-glazed glass is the most energy efficient on the market, offering exceptional insulation performance. Triple-glazed low-E windows often achieve a rating of A++ (the highest rating possible).
Several factors influence the final cost of casement windows, including size, materials and glazing.
The larger the window, the higher the cost, with premium window frame materials such as wood costing more than options such as uPVC.
Here’s a comprehensive breakdown.
The size of your casement windows directly impacts the cost. Larger windows, especially double, triple, bow or bay windows, cost significantly more than standard single windows.
The window frame material greatly impacts the cost of the window, with wood, composite and aluminium being higher-end options.
This material is popular in the UK due to its durability, energy efficiency and affordability.
For standard uPVC casement windows, you can generally expect to pay between £250 and £600 per window, including installation.
Wood casement windows look great and offer excellent insulation, but they come at a higher cost than uPVC.
Costs for timber windows typically start around £800 and can extend well over £2,000 per window, installation included.
Aluminium casement windows also carry a higher cost than uPVC.
Prices can vary significantly depending on size, window design and finish but typically start from around £700 and go up to £2,500 per window, including installation.
Composite casement windows vary widely in price, from budget-friendly options to high-end varieties made from premium materials like oak.
Due to the complex manufacturing process and the high-quality materials, composite windows range from around £1,000 to £3,000 or more per window.
The type of glazing also affects the cost of the window. Double glazing costs the least so is the go-to option, but triple glazing and low-E glass have become more affordable in recent years. Though more expensive upfront, opting for triple glazing or low-E glass can improve your home’s energy efficiency.
Hardware is an often-overlooked cost.
Window hardware includes handles and locks, with high-quality multipoint locking systems costing more than their single-lock counterparts. Window handles also vary in price.
Casement windows are known for their versatility. As one of the more widespread window types, they’re affordable and come in many different materials. However, there are a couple of downsides to be aware of.
Here are the pros and cons of casement windows.
One of the standout advantages of casement windows is their superb ventilation.
They open wide, and the window sash acts as a funnel, capturing side breezes from across the property and directing them inside. Other window styles don’t readily allow you to catch and direct breezes into the house.
Casement windows often lack the muntin bars (the strips of wood, vinyl or metal that divide panes of glass) typically found in other window styles, such as traditional sash windows.
This offers a less obstructed, panoramic outdoor view.
Casement windows typically feature a multipoint locking mechanism, which secures the window at multiple points with just one handle.
This built-in design means the lock can’t be moved from outside, making it difficult for potential intruders to break in. Furthermore, sash windows close inwards, which helps prevent forced entry.
Casement windows come with a handle mechanism, making them easy to operate.
This is advantageous for windows in hard-to-reach places, like above kitchen sinks or high on a wall. Moreover, the mechanism rarely sticks, as can be the case with sash or sliding windows.
While casement windows can be built relatively tall and wide, there are practical limitations to how wide they can be.
The window sash, which swings open, must be able to support its weight when opened, limiting width. Moreover, very large casement windows may be prone to stress in high winds.
Given that casement windows swing outwards to open, they might not be suitable for areas adjacent to walkways, patios, decks or other high-traffic areas outside the home.
The outwards swing could obstruct or limit usable exterior space, a consideration for properties with small gardens or patios.
Before you search for casement window quotes, having a clear idea of what you’re looking for helps ensure you get the best deal.
This includes the window type, frame material, glazing, hardware (such as locks and handles) and finishes (such as paint or stain). From there, you can start collecting and comparing quotes.
Here are a few things to consider before collecting and comparing quotes.
Look for a window company with a strong track record, plenty of good reviews and a portfolio of successful work. If you’re looking for specialist windows, such as wood or composite, look for installers proficient with those materials.
Installers operate locally and nationally; large national installers such as Everest and Anglian Home Improvements are not always the best options, so shop around for local quotes too.
Understanding the warranty that accompanies your new casement windows is crucial.
Most reputable window installation companies in England and Wales should be registered with Fenestration Self-Assessment Scheme (FENSA).
FENSA is a government-authorised scheme to monitor building regulation compliance for windows and doors. FENSA registration means the installer is obligated to provide an insurance-backed warranty.
In the UK, windows are rated by the BFRC on a scale from A++ (most energy efficient) to E (least energy efficient).
A good quote should specify the energy performance ratings of the proposed windows, which should meet or exceed the current UK energy efficiency standards.
Windows with high energy ratings might cost more initially, but they can save you money in the long run by reducing energy consumption and heating costs.
The quote should also provide information about the installation process. This includes the estimated timeline for the installation, the expected start and completion dates and details of any potential disruption to your daily routine, such as the need to clear rooms.
Preparing for installation will save time and prevent unforeseen snags in the installation process.
A good quote will always provide an itemised breakdown of costs, including the windows, materials used, labour charges and additional costs such as delivery fees or old window disposal.
A well-itemised list will help you understand where your money is going and allow you to compare quotes accurately. Don’t hesitate to ask for clarification if anything in the quote is unclear. It could also be worth checking if you qualify for a window replacement grant before signing off on a quote.
Accreditations and certifications are endorsements from recognised industry bodies that validate window installers’ competence and credibility.
Certifications demonstrate that a company meets specific quality and performance standards.
Here are some of the main accreditations to look out for:
Casement windows are a rock-solid, flexible option that suits most homes.
With a simple swing-outwards mechanism, casement windows offer superb ventilation and excellent views. Moreover, casement windows are versatile and available in various styles and sizes, with many finishes and glazing options.
When searching for casement window quotes, be sure to search for a reputable company with an established track record, good reviews and a portfolio of recent work.
Look for insurance backed-warranties and detailed quotes that list everything, including window materials, glazing and hardware options and delivery fees.
Yes, flush casement windows are typically more expensive than standard casement windows.
With flush casement windows, the window sits in line with the frame for a sleek, uniform look. Otherwise, they’re near-identical to standard casement windows. The disadvantages of flush casement windows are the higher cost than standard casement windows.
Typically, casement windows open outwards to provide better ventilation and a full, unobstructed view.
However, some models may open inwards based on specific needs or preferences, although this is rare.
It’s essential to consider the space and location where the window will be installed to ensure it can function safely.
Yes, you can paint casement windows. However, the process will depend on the window material. For wood casement windows, you must lightly sand the surface, apply a primer and then paint.
For aluminium casement windows, special preparation and paints are needed for the paint to adhere correctly.
Always protect the window’s operational mechanisms from paint to keep them functioning smoothly. Lastly, remember that painting might void your window’s warranty, so it’s best to check this beforehand.
