Casement windows are one of the most familiar styles of window in the UK. You’ll find them on all sorts of properties, from Victorian terraces and Edwardian houses to newer family homes and contemporary extensions.

They are also one of the most versatile. Casement windows can be made in timber, uPVC, aluminium and timber alternative materials, with different profiles, colours, glazing and hardware available to suit the property.

If you’re looking at replacing your windows, it’s worth spending some time considering the style as well as the material. A window that looks right on a modern extension may not be the best choice for a Victorian terrace, even if the two products have similar performance figures.

With over 60 years of experience, we’ve worked on a wide range of homes across Surrey and South London. Here’s what to look for when choosing casement windows.

What are casement windows?

A casement window has an opening section that is attached to the frame with hinges. Most open outwards from the side, although different configurations are available.

They can be used as individual windows or combined with fixed panes to create larger openings. This makes them suitable for everything from smaller bedrooms and bathrooms to larger living spaces.

Casement windows are popular partly because they are straightforward. There’s no complicated mechanism, and modern designs offer good security, ventilation and thermal performance.

They also leave plenty of scope for getting the appearance right.

Choosing the right style

The term ‘casement window’ covers quite a broad range of designs.

A standard casement has an opening section that sits slightly proud of the frame when closed. A flush casement has a flatter profile, with the opening section sitting level with the frame.

Flush casements are often chosen for traditional properties because of their simpler appearance, but they aren’t the only option for a period home.

The proportions of the window, the number of panes, glazing bars, colour and hardware can all make a difference. It’s worth looking at the window as part of the whole house rather than choosing a style in isolation.

uPVC casement windows

uPVC remains a popular material for replacement windows, and modern systems are a long way from some of the bulkier designs seen in the past.

Today’s uPVC windows are available in a good range of colours and finishes, with profiles that can work on both traditional and contemporary homes.

They’re also relatively easy to look after. There’s no regular painting required, and the frames can generally be kept clean with little more than a cloth and soapy water.

At Elwyns, our uPVC windows come from Whiteline and Everglade.

For homeowners replacing a number of windows, uPVC can offer a sensible balance between cost, performance and maintenance.

Timber casement windows

If you’re working on a period property, timber is often worth considering.

There’s a warmth to natural timber that can be difficult to reproduce with another material. It also allows for traditional proportions and details, which can be particularly important when replacing older windows.

Our timber windows are supplied by Timber Windows.

Timber does need more care than uPVC or aluminium. Depending on the finish and exposure, it will need to be maintained and redecorated over time. For some homeowners, that’s a worthwhile trade-off for the appearance and character that timber provides.

It’s also worth considering the existing windows. If the house has traditionally detailed timber casements, replacing them with something that looks noticeably different can have a bigger impact on the appearance of the property than you might expect.

Aluminium casement windows

Aluminium is a good option if you’re looking for slimmer frames and more glass.

Its strength means that frames can be made relatively narrow without compromising their ability to support larger panes. This makes aluminium particularly popular for contemporary homes, extensions and rooms where making the most of natural light is important.

Modern aluminium windows are also thermally broken, so the performance is very different from older aluminium windows that you may remember from decades ago.

We offer aluminium windows from Sheerline and Aluco.

Aluminium doesn’t have to mean a stark, ultra-modern appearance either. The right colour and configuration can work well alongside a wide range of architectural styles.

Timber alternative casement windows

If you like the appearance of timber but don’t want quite as much maintenance, timber alternative windows are another option.

Our timber alternative windows come from Evolution, which offers designs based on traditional timber windows.

The range includes flush and lipped casements. A lipped casement has a more defined profile around the opening section, while a flush casement has a flatter appearance.

This can be useful when replacing windows on a period or character property. You can choose a profile that reflects the style of the existing windows while benefiting from a modern, lower-maintenance material.

For homeowners who want the look of painted timber without having to repaint the windows as regularly, it’s an option worth looking at.

Are casement windows energy efficient?

Modern casement windows can be very energy efficient, but the material isn’t the only thing that matters.

The glass, frame, seals and installation all contribute to the finished performance.

If you’re replacing older windows, particularly single glazing or older double glazing, the difference can be noticeable. Newer glazing is designed to reduce heat loss and modern frames provide a much better seal around the opening.

It’s also worth remembering that installation matters. A good window won’t perform properly if it hasn’t been fitted correctly.

When we’re looking at a replacement window project, we consider the product and the property together rather than simply recommending the same specification for every house.

What about security?

Security is another reason homeowners choose to replace older windows.

Modern casement windows can be fitted with more advanced locking systems and stronger glazing than many older windows. The frame, hardware and installation all contribute to the overall security of the finished window.

It’s worth discussing the options with your installer, particularly for easily accessible ground-floor windows.

Are casement windows suitable for period homes?

They certainly can be.

Casement windows are found on many Victorian and Edwardian properties, so replacing them with a well-designed casement doesn’t necessarily mean losing the character of the house.

The detail is what matters.

A Victorian terrace might benefit from traditional proportions and glazing bars, while a more modern property could suit larger panes and slimmer frames.

The colour is important too. White isn’t the only option, and a carefully chosen heritage shade can make a replacement window feel much more settled within the existing architecture.

If your property is listed or in a conservation area, check whether there are any restrictions before replacing the windows. The requirements can vary from one property to another.

How much do casement windows cost?

There’s no useful one-size-fits-all price for replacement casement windows.

The cost will depend on the number of windows, their size and configuration, the material, glazing, colour, hardware and installation.

uPVC is generally the more affordable option, while timber and aluminium tend to sit at a higher price point. Timber alternative windows offer another option between the two, depending on the specification.

When comparing quotations, make sure you’re comparing the same things. Two windows can look similar on paper but have very different glazing, hardware, profiles or installation specifications.

The cheapest quotation isn’t always the cheapest option in the long run.

What should you consider before replacing your windows?

Start with the house.

Look at the windows you already have and consider what works about them. Are the proportions right? Do you want to keep the same appearance? Are you looking for something more modern?

Then think about how you use the rooms. You may want more natural light in a kitchen or living room, while ventilation and privacy might be more important upstairs.

Maintenance is another consideration. Timber needs more ongoing care than uPVC, while aluminium offers a durable finish with relatively little maintenance.

And, of course, there’s the budget.

A good window company should be able to talk you through the options rather than simply showing you the most expensive product.

Why choose Elwyns?

Elwyns has been established since 1963, so we’ve been installing windows and doors for more than 60 years.

During that time, we’ve worked on all sorts of properties, and we’ve learnt that there isn’t one window that’s right for everyone.

Some homes need the character of timber. Others are better suited to low-maintenance uPVC. An extension might call for aluminium, while a period property could benefit from a timber alternative with traditional detailing.

We work with a selection of established manufacturers, including Timber Windows, Whiteline, Everglade, Sheerline, Aluco and Evolution, so we can look at the project as a whole before recommending a product.

We also understand that replacing your windows isn’t something you do very often. It’s a significant investment, which is why we aim to make the process straightforward and give you advice that makes sense for your home.

And because we’ve been around for over six decades, we’re still here if you need us after the installation. Our guarantees and aftercare are part of that commitment.

See our casement windows in person

Choosing new windows from a photograph isn’t always easy.

If you’re considering casement windows, you’re welcome to visit one of our showrooms in Carshalton, Dulwich or Woldingham. You can see different materials, profiles, colours, glazing and hardware and talk through your options with our team.

Whether you’re replacing one window or planning a larger project, we’ll help you find an option that works for your property.

Get in touch with Elwyns or visit one of our showrooms to discuss your new windows.

Replacing your windows is one of those jobs where the practical decisions and the appearance of your home tend to go hand in hand.

You might want warmer rooms, better security and windows that are easier to maintain, but that doesn’t mean you want to lose the character of your house in the process. This is particularly true in Carshalton, where there are plenty of Victorian and Edwardian homes alongside 1930s properties and more contemporary houses.

For many period properties, timber has traditionally been the natural choice. It looks right, can be made with traditional details and has a character that is difficult to reproduce.

Timber alternative windows have come a long way in recent years. Modern designs can replicate many of the details associated with traditional timber windows while offering the lower maintenance and modern performance that homeowners often want.

At Elwyns, we supply Evolution timber alternative windows, alongside genuine timber, uPVC and aluminium. So, if you’re considering new windows for your Carshalton home, how do you know whether timber alternative is the right choice?

What are timber alternative windows?

Timber alternative windows are made from modern materials rather than natural wood, but are designed to recreate the appearance of traditional timber windows. A convincing timber alternative isn’t simply a modern window with a wood-effect finish.

The profile of the opening sash, the proportions of the frame, the joints, cill and glazing all contribute to how the finished window looks.

Evolution has focused heavily on these details. Its two main window ranges are Storm and Evolution Flush. Storm is based on the appearance of traditional stormproof timber casements, while Evolution Flush is designed to replicate the flatter appearance of traditional flush-fitting timber windows. Both are available with timber-style joints.

That gives homeowners more choice when replacing existing windows, particularly if the original windows have a distinctive traditional appearance.

Why consider timber alternative windows in Carshalton?

The style of a replacement window can have a surprisingly large effect on the appearance of a house.

On a period property, the windows aren’t just functional. Their proportions and detailing form part of the architecture.

If you have a Victorian or Edwardian home with traditional casement windows, for example, replacing them with a modern-looking window may make the house feel very different. It doesn’t necessarily mean the replacement is a bad window, but it may not be the right window for that particular property.

Timber alternative windows offer another route.

You can retain traditional-looking profiles and details while choosing a product designed for modern living. This can be particularly appealing if you like the look of timber but don’t want the ongoing work that comes with maintaining painted wooden frames.

Of course, every property is different. Genuine timber may still be the better choice for some homes, particularly where authenticity is the main consideration.

Evolution timber alternative windows

Evolution is the timber alternative manufacturer we work with at Elwyns.

The company has built its window range around traditional window design rather than treating heritage styling as an afterthought. Its Storm and Flush windows are designed to retain features associated with timber joinery while incorporating modern window technology. Which works best depends on the house.

If you’re replacing existing windows, it’s worth looking closely at what you already have. Sometimes a small detail, such as the profile of the opening section or the arrangement of the glazing bars, makes more difference than you might expect.

Timber or timber alternative?

Genuine timber remains a beautiful material and is still the right choice for many homeowners. It has a natural warmth, can be repaired and redecorated, and allows for a high level of traditional detailing.

Our timber windows are supplied by Timber Windows, and they are worth considering if natural material and traditional craftsmanship are particularly important to you. The downside is maintenance.

Painted timber needs to be looked after. The exact amount of maintenance will depend on the finish and exposure of the property, but eventually the frames will need decorating.

That’s not necessarily a problem. For some homeowners, it’s simply part of having a traditional timber window.

For others, particularly those replacing a large number of windows, it is something they’d rather avoid.

Evolution windows are designed to provide a timber-style appearance without the regular sanding and repainting associated with painted timber. Evolution describes its products as low-maintenance and long-lasting, with routine care largely involving cleaning and looking after the moving parts.

So the decision comes down to what matters most to you: the natural material of timber, or the reduced maintenance of a modern alternative.

Storm or Flush?

If you’ve started looking at Evolution windows, you’ll probably come across both terms.

A Storm casement has a more pronounced profile, with the opening sash overlapping the frame. It is based on the traditional stormproof timber casement. Whereas a flush casement is flatter and when the window is closed the sash sits level with the frame.

Neither is automatically more traditional or more appropriate. It depends on the property and the look you’re trying to achieve.

There are other details to consider too. Evolution windows can incorporate timber-style joints, traditional glazing bars and decorative glass, while a range of colours and finishes is available.

If you’re replacing existing windows, we’d always recommend looking at the old ones carefully before choosing a replacement. The details may give you a good starting point.

What about lipped casements?

Lipped casements are another style worth knowing about if you’re looking for traditional-looking windows.

The opening section has a more defined profile, rather than sitting completely flush with the outer frame. This is a familiar detail on many traditional timber windows.

Evolution’s Storm range is designed around this type of traditional stormproof casement, while the Flush range offers the flatter alternative.

It’s a relatively small difference, but it can change the character of the finished window.

This is why we don’t think choosing windows should come down to looking at a product photograph and picking a colour. The profile, glazing and proportions all need to work together.

What do Evolution windows look like?

This is often the first concern homeowners have when considering a timber alternative.

Nobody wants to replace beautiful old timber windows with something that looks out of keeping with the property.

Evolution has tried to address this by putting a lot of emphasis on traditional details. Its windows feature timber-style joints and are available in both traditional and more contemporary configurations.

There’s also plenty of scope to change the overall appearance through the specification.

You can choose different glazing arrangements, colours and finishes, while traditional glazing bars and decorative glass can be used where appropriate.

That means the same basic window system can look quite different depending on how it is specified.

This is particularly useful for period properties, where a simple change in glazing pattern or colour can make the difference between a window that looks right and one that doesn’t.

How much maintenance do they need?

One of the main reasons people choose timber alternatives is the maintenance.

Traditional painted timber windows need to be periodically prepared and redecorated. Timber alternative windows are designed to avoid that routine.

Evolution describes its windows as low-maintenance and recommends straightforward cleaning and routine care to keep them looking and operating properly.

You will still need to clean the frames and glass, and the hardware and moving parts should be looked after. But there is no regular cycle of sanding and repainting the frames.

If you’re replacing ten, fifteen or twenty windows, that difference can become quite significant over the years.

Are timber alternative windows energy efficient?

Improving energy efficiency is often one of the reasons homeowners decide to replace older windows in the first place.

Evolution’s windows combine their traditional styling with modern glazing and frame technology. Elwyns currently states that its Evolution timber alternative windows can achieve U-values as low as 1.2 W/m²K, depending on specification. The range can also be specified with modern double glazing, warm-edge spacer bars and triple glazing options.

The exact performance will depend on the specification you choose.

It’s also important not to look at the glass or frame in isolation. Installation, seals and the condition of the surrounding building will all have an effect on the finished result.

If your existing windows are draughty, difficult to operate or suffering from failed glazing, replacing them with a modern system can make a noticeable difference to the comfort of the house.

What about security?

Modern replacement windows can also offer considerably more security than older windows.

Evolution’s systems incorporate modern locking hardware, while the overall design is built around current performance requirements. The precise security specification will depend on the window and hardware selected.

This is worth discussing when you’re choosing your windows, particularly for easily accessible ground-floor openings.

It is another example of why replacing windows isn’t just about how they look. The right specification should work for the way you actually live in the house.

Can they be used in conservation areas?

This is particularly relevant when replacing windows on older properties.

Timber alternative windows can be suitable for some conservation-area properties because they are available with traditional detailing and profiles. Elwyns regularly works on period properties and can advise on appropriate specifications and provide drawings where required.

Conservation areas have different requirements, and listed buildings can have additional restrictions. You should always check what applies to your property before ordering replacement windows.

If planning approval or other consent is required, the design and appearance of the proposed windows may need to be considered as part of that process.

Are timber alternative windows right for a 1930s home?

1930s houses are particularly interesting because they often sit somewhere between traditional and modern design. Some have simple casement windows, while others feature more distinctive glazing patterns or period details.

Evolution’s Storm range can work well where you want to retain a more traditional casement appearance, while the Flush range offers a cleaner alternative.

There’s no need to make the windows look artificially old, either. A simple profile and carefully chosen colour can work very well on a 1930s house without turning it into a pastiche.

The same principle applies to extensions. If you’ve added to an older property, timber alternative windows can help the new and old parts of the house feel more connected.

How much do timber alternative windows cost?

There isn’t a standard price for timber alternative windows.

The cost will depend on the size and number of windows, their configuration, glazing, colour, hardware and the installation itself.

A straightforward casement will naturally cost less than a more involved design with decorative glazing, Georgian bars or other bespoke details.

It’s also worth comparing quotations carefully. Make sure you’re looking at the same specification rather than simply comparing the headline price.

A cheaper window may have different glazing, hardware or installation included, so it isn’t always a direct comparison.

For something you’re likely to live with for many years, the quality of the product and installation matters just as much as the initial price.

A real Elwyns project

One of the best ways to understand where timber alternatives work is to look at a finished project.

At Weald Cottage, a 1930s property in Woldingham, the owners were carrying out an extensive renovation and needed to replace all of the windows and doors.

They had originally considered timber but were concerned about the cost. After visiting the Elwyns showroom, they chose Evolution alternative timber-look casement windows instead.

Twelve windows were installed alongside French doors with sidelights and a timber entrance door. The homeowners were particularly pleased with how closely the windows fitted the traditional character of the cottage, commenting that they had received many compliments on the finished result.

It’s a good example of why the choice doesn’t have to be simply ‘timber or uPVC’. There is another option for homeowners who want traditional styling but have different priorities when it comes to maintenance and budget.

Why choose Elwyns?

We’ve been established in Carshalton since 1963, so we’ve spent more than six decades working with homeowners on replacement windows and doors.

We don’t think there is one material that suits every property. That’s why we offer a choice of timber, timber alternative, uPVC and aluminium.

Alongside Evolution, we work with Timber Windows, Whiteline, Everglade, Sheerline and Aluco, allowing us to look at the house first and then recommend products that suit it.

That experience is particularly useful when you’re working on an older property. Sometimes the right answer is genuine timber. Sometimes a timber alternative is a better fit. And sometimes another material makes more sense altogether.

Our Carshalton showroom is also a useful place to compare the different options before making a decision.

Most importantly, we’re still here once the installation is finished. We’ve been around for over 60 years, and we intend to continue looking after the customers who have trusted us with their homes.

Visit our Carshalton showroom

If you’re considering timber alternative windows in around Sutton or Surrey, we’d recommend seeing the different options for yourself.

Our showroom at 112–114 High Street, Carshalton gives you the chance to compare Evolution windows with other materials and look at the different profiles, colours, glazing and hardware in person.

You can talk through your property with our team, bring photographs or plans if you have them, and get a better idea of which options might suit.

You don’t have to know exactly what you want before you come in. That’s what we’re here for.

Visit Elwyns in Carshalton or get in touch to arrange a home visit and discuss your replacement windows.

Replacing your windows is one of the most significant projects you can do for your home. New windows can enhance kerb appeal, improve comfort and reduce heat loss. A popular question that appears when people start looking into replacing them is the material, quite often: should I choose uPVC or aluminium windows?

Both uPVC and aluminium have evolved and improved a lot over the last decade. Modern uPVC windows are stronger, more resilient and available in a wider range of styles than ever before, while today’s aluminium offer good thermal performance alongside their slim, contemporary appearance.

At Elwyns, we’ve been helping homeowners across Surrey and South London choose replacement windows for more than 60 years. We take time to understand your property and help you find windows that will look right and perform well for many years.

Understanding the Difference

The biggest difference between uPVC and aluminium windows is the frame material, but that affects more than appearance.

uPVC is a durable, low maintenance material that has been used in window manufacturing for many years. Modern systems are designed to provide reliable insulation and are available in both traditional and contemporary styles.

Aluminium offers a stronger frame, allowing for slimmer sightlines and more glass. Advances in thermal break technology mean modern aluminium windows are now highly energy efficient, making them suitable for both new-build homes and renovation projects.

Both materials can deliver excellent results when manufactured to a high standard and installed correctly.

Appearance

uPVC Windows

Modern uPVC windows are far removed from the bulky white frames from the 1980s and 1990s. Available in a wide choice of colours, woodgrain finishes and frame styles, uPVC windows today are suitable for everything from traditional cottages to contemporary family homes.

Flush casement designs, decorative glazing bars and heritage-inspired detailing have made uPVC an increasingly popular choice for period properties where planning restrictions don’t require timber.

Aluminium Windows

Aluminium windows offer a cleaner, more contemporary look.

Because aluminium is naturally strong, the frames can be slimmer without compromising performance. This creates larger glazed areas and allows more natural light into the home.

They work particularly well in:

• Contemporary homes
• Kitchen extensions
• Garden rooms
• Homes with large openings
• Modern renovations

That doesn’t mean aluminium is only suited to new properties. Many homeowners choose aluminium for the rear of a traditional home while retaining a more traditional appearance at the front.

Energy Efficiency

Energy efficiency is often one of the main reasons people replace their windows.

Both uPVC and aluminium windows are designed to meet modern performance standards and, when fitted correctly, can make a significant difference to the comfort of your home.

Modern windows typically include:

• High-performance double or triple glazing
• Low-emissivity glass
• Warm edge spacer bars
• Advanced weather seals

While uPVC has long been recognised for its insulating properties, advances in aluminium frame design mean the gap between the two materials is much smaller than it once was.

In reality, the quality of the window system and the installation are often more important than the material itself.

Maintenance

Both materials are relatively easy to look after, but there are some differences.

uPVC windows require very little maintenance. A regular clean with warm soapy water is generally all that’s needed to keep the frames looking their best.

Aluminium windows are equally straightforward to maintain. Their powder-coated finish is highly durable and designed to withstand the British weather without peeling or flaking.

Whichever material you choose, good-quality windows should continue to perform well with very little ongoing maintenance.

Strength and Durability

Aluminium has a natural strength that makes it particularly well suited to larger window designs.

If you’re planning wide openings or want slimmer frames with more glass, aluminium is often the preferred option.

uPVC is also an extremely durable material and performs exceptionally well in everyday residential settings. Modern manufacturing techniques have significantly improved both strength and longevity, making it a dependable choice for most homes.

The key is choosing quality products. Lower-specification windows, regardless of material, are less likely to provide the same long-term performance.

Which Is Better for Period Homes?

Many Victorian and Edwardian homes suit traditional flush casement or sliding sash windows in uPVC, particularly where homeowners want to improve energy efficiency while keeping maintenance to a minimum.

For homes where authenticity is the priority, timber may still be the most appropriate option, especially in conservation areas or listed buildings.

Aluminium is increasingly being used for rear extensions on period homes. This allows homeowners to enjoy larger glazed areas without affecting the traditional appearance of the front of the property.

Cost

Budget is naturally an important consideration.

In most cases, uPVC windows are the more affordable option, making them a popular choice for homeowners replacing several windows at once.

Aluminium windows generally represent a higher initial investment, reflecting both the material and the manufacturing process.

However, it’s worth looking beyond the initial quotation.

The quality of the product, the standard of installation and the level of aftercare can all have a greater impact on long-term value than the purchase price alone.

The Importance of Installation

Even the highest-quality window won’t perform as intended if it isn’t installed correctly.

Poor installation can lead to:

• Draughts
• Water ingress
• Reduced thermal performance
• Difficulty opening and closing windows
• Premature wear

That’s why choosing an experienced installer is just as important as choosing the right material.

At Elwyns, every installation is carried out with care and attention to detail, ensuring your new windows perform as they should from day one.

The Windows We Recommend

At Elwyns, we work with manufacturers we know and trust.

Our uPVC windows are supplied by Whiteline and Everglade, offering a wide range of styles suitable for both traditional and contemporary homes.

Our aluminium windows come from Sheerline and Aluco. Sheerline offers modern, thermally efficient systems with slim sightlines, while Aluco specialises in steel-look aluminium windows that are particularly popular for heritage properties, internal screens and contemporary extensions.

By offering carefully selected ranges rather than every product on the market, we’re able to recommend solutions that we’ve seen perform well over many years.

So, Which Should You Choose?

So, Which Should You Choose?

uPVC windows are an excellent choice if you’re looking for:

• Excellent value
• Low maintenance
• Strong thermal performance
• A wide choice of styles and finishes

Aluminium windows are worth considering if you want:

• Slimmer frames
• Larger glazed areas
• A contemporary appearance
• Exceptional strength and durability

The right choice depends on your home, your budget and the style you’re trying to achieve.

Why Choose Elwyns?

Replacing your windows is a significant investment, and it’s important to work with a company you can trust.

Established in 1963, Elwyns has built its reputation on honest advice, quality workmanship and carefully selected products. Many of our customers come to us through recommendation or return to us for future projects because they know we’ll recommend what’s genuinely right for their home.

We also provide comprehensive guarantees and ongoing aftercare, giving you confidence that if you ever need us, we’ll be here to help.

Visit One of Our Showrooms

Choosing between uPVC and aluminium windows is much easier when you can see the differences for yourself.

Visit one of our showrooms in Carshalton or Dulwich to compare styles, finishes and colours, and speak to our experienced team.

Whether you’re replacing a single window or renovating your entire home, we’ll help you find windows that complement your property and are built to last.