uPVC flush windows have become increasingly popular among homeowners seeking a blend of traditional aesthetics and modern performance. Characterised by window sashes that sit flush within the frame, these windows offer clean lines and an elegant appearance suitable for both period properties and contemporary homes. However, choosing the right one can be daunting with numerous brands available.
Looking for flush casement or timber-look windows? The Door and Window Experts Website has created this buying guide for uPVC flush and timber-look PVCu windows. In this comprehensive guide, we’ll delve deeper into some of the leading uPVC flush window brands—Evolution, Residence Collection, Liniar, Deceuninck, Rehau, Profile 22, and Kommerling—highlighting their unique features, benefits, and what sets them apart.
What are uPVC flush windows?
With uPVC flush windows, the opening sash of the window sits flush with the outer frame, giving a flat, seamless look. You will also see them referred to as uPVC flush sash windows and uPVC flush casement windows; they are the same product.
The sash is part of the window frame that holds the glass panes in place and is the opening element– the sash then either slides to open or close, like Victorian windows on rope pulleys or opens via a hinge called a casement.
The casement is part of the window that hinges at the side, top, or bottom to open and close the window outward.
The difference between a regular uPVC casement and uPVC flush windows is a regular casement frame protrudes. In contrast, a flush casement lies flat against the outer frame, giving a more modern aluminium window or traditional wood window look.
Internally, windows can be flush inside or have a decorative non-flush appearance.
How to choose the best uPVC flush windows
When selecting uPVC flush windows, you must consider why you’d want this style of windows and if they are the best option for your home. By far, the intent behind all of these windows is to replicate the look of genuine wood windows, and uPVC does it better than aluminium.
- Authentic appearance: Windows replicate traditional timber designs, especially important for heritage properties or conservation areas.
- Aesthetics: The window’s look should complement the property’s style, whether it’s a quaint cottage or a sleek modern home.
- Balanced sightlines: The advantage of flush windows is their ‘dummy sash’ design, giving you equal glass sizes and balanced window sightlines.
- Energy efficiency: High thermal performance to keep homes warm and reduce energy bills.
- Security: Robust locking mechanisms and features for peace of mind.
- Customisation: A wide range of colours, finishes, hardware, and glazing options.
- Quality installation: Professional fitting to ensure optimal performance and longevity.
Comparing uPVC with aluminium, timber and hybrid-composite flush windows
It’s right to compare other materials with uPVC, and our advice here is simple: uPVC windows are better in virtually every respect than other materials. Timber, of course, is the genuine article. If you can stretch to the additional cost, you’ll be rewarded with a luxury look and feel, optimum quality and long service life that uPVC as a material can only dream of.
Comparing uPVC to aluminium and hybrid-composite flush windows does not compare like for like. Whilst the benefits of aluminium vs uPVC windows are now well known, for flush casement and timber-look windows, uPVC does it best. Getting the foiled wood finishes, mechanical timber-look joints, and period frame styling with uPVC is also easier, cheaper, and faster.
Disregard the sales messages about high maintenance on timber windows and get professional advice on what is actually needed to care for and live with genuine wood windows. We can tell you the guarantees on timber windows are now as long as other materials when you buy the right product. Think aluminium is 100% maintenance-free? Damage the paint finish on an aluminium window and leave it without repair, and it won’t be long before you see bubbling paint, corroded metal and a damaged product. Whether painted wood or powder-coated coloured aluminium, no painted window is fit, forget, and maintenance-free.
Brands overview
Selecting the perfect uPVC flush windows for your home is a decision you can make based on the key design factors of the product, which are:
- Overall appearance: flush outside only or flush both sides of the windows
- The overall colour, wood foil or textured and grained foil
- The choice of welded, mechanical or timber-look joint
- Price point
- Confidence in your chosen supplier and installer
Evolution Windows
Positioning: Upper-level luxury
Overview:
Evolution Windows were the first timber-look product in uPVC of its kind, and today, Evolution Windows stands out as a premium manufacturer that successfully marries the classic beauty of timber with the advantages of modern technology.
Their windows are designed to emulate the look and feel of traditional wooden windows with the uPVC material benefits. Much thought and attention to detail has gone into Evolution Windows and in our view, these upper-level windows that look the part.
Key features:
- Authentic timber aesthetics: Evolution’s flush windows feature handcrafted joints and intricate period detailing, closely replicating the appearance of traditional timber windows.
- Customisation options: With over 200 RAL colours available, homeowners can personalise their windows to match their property’s aesthetic. Options include standard painted finishes, natural wood colours, and bespoke colour matching.
- Glazing choices: The windows come standard with double glazing, achieving U-values of 1.4 W/m²K or better. There’s also the option to upgrade to triple glazing for enhanced energy efficiency or acoustic glass for improved sound insulation.
- Innovative “Invisiline” design: This feature reduces the sightline across mullions to 127mm from the standard 162mm, resulting in slimmer frames and larger glass areas, thereby increasing natural light inside the home.
- Superior security: Evolution windows incorporate high-security multi-point shootbolt locking systems, easy escape egress hinges, and are independently tested to meet British and European standards.
- Hardware choices: A range of traditional and contemporary hardware options are available, including wrought iron handles and peg stays in various finishes like black, pewter, chrome, and gold.
Why choose Evolution Windows?
The first of its kind in uPVC timber-look windows, Evolution Windows are ideal for homeowners seeking the most authentic timber-like appearance without maintenance. Their commitment to craftsmanship and modern performance positions them at the luxury end of the market.
Residence Collection
Positioning: Upper-level luxury
Overview:
The Residence Collection is outstanding. It is expertly crafted, beautiful to look at, tactile, elegant and ultra-premium. The Residence Collection offers a suite of premium window and door systems designed and made in Great Britain.
Their windows are crafted to authentically replicate 19th-century timber designs authentically, making them suitable for period properties, including those in conservation areas.
Key features:
- Residence 9 (R9): Features a flush exterior with a decorative interior, closely emulating traditional timber windows with modern benefits like energy efficiency and low maintenance.
- Residence 7 (R7): Offers a flush appearance on both the inside and outside, providing a sleek, contemporary aesthetic suitable for modern homes.
- Authentic design details: The windows replicate historical designs and adhere to conservation guidelines, making them ideal for heritage properties.
- Energy efficiency: The multi-chambered design and modern glazing options contribute to excellent thermal performance, keeping homes warm and reducing energy bills.
- Customisation: A wide range of colours and finishes are available, allowing homeowners to personalise their windows. Options include both traditional and contemporary shades.
- Hardware options: Traditional hardware such as monkey-tail handles and peg stays enhance the authentic look.
Why choose Residence Collection?
If authenticity is paramount—especially for period properties—the Residence Collection provides windows that meet conservation requirements while offering modern performance. Their products are meticulously designed to blend old-world charm with contemporary benefits.
Deceuninck Heritage
Positioning: Premium
Overview:
Deceuninck is a global leader in uPVC window systems, and their flush windows are part of their Heritage Window Collection.
These windows are designed to seamlessly blend with any property style, offering the aesthetic appeal of timber with modern performance.
Key features:
- Slim sightlines: The windows feature slim and aesthetic profiles that maximise the glass area, allowing more natural light into the home.
- Heritage Flush Sash windows: Ideal for traditional properties, these windows fit flush within the frame and replicate the look of classic timber windows.
- Energy efficiency: Deceuninck’s flush windows are designed to be thermally efficient, contributing to reduced energy bills. They can achieve high energy ratings due to their multi-chambered profiles.
- Sound insulation: The windows offer superior sound insulation, making them suitable for properties in noisy environments.
- Colour options: With over 20 colourways available from stock, including heritage colours, homeowners have a wide range of choices to match their property’s character.
- Long-lasting finishes: The finishes are designed to be vibrant and durable, requiring minimal maintenance over time.
Why choose Deceuninck?
Deceuninck flush windows are ideal for homeowners looking for a balance between traditional aesthetics and modern performance. Their extensive colour range and focus on energy efficiency make them a versatile choice for various property types.
Liniar Flush
Positioning: Mid-level
Overview:
Liniar offers innovative uPVC flush sash windows that combine traditional aesthetics with modern technology. They provide two main flush window systems: the 70mm range and the 80mm Resurgence range.
Key features:
- 70mm flush sash:
- Traditional appearance: Designed to mimic the look of timber windows, these windows have no overlapping frames, resulting in a sleek, flush finish.
- Energy efficiency: Achieves A+ energy ratings with U-values as low as 1.2 W/m²K, thanks to Liniar’s multi-chambered profiles and patented bubble gasket.
- Customisation: Available in a variety of colours and finishes, including woodgrain foils, to suit both traditional and modern homes.
- Low maintenance: uPVC construction ensures durability without the need for regular painting or varnishing.
- 80mm Resurgence flush sash:
- Double-rebated seal: An innovative feature that eliminates visible gaskets between the frame and sash, enhancing both aesthetics and weather performance.
- Enhanced thermal efficiency: The double-rebated seal provides superior insulation, lowering energy bills.
- Foiled Interiors: The interior surfaces are also foiled, providing a realistic timber-look finish even when the window is open.
Why choose Liniar?
Liniar’s flush windows are suitable for homeowners seeking the traditional look of timber with the benefits of modern uPVC at a more accessible price point. The Resurgence range, in particular, offers enhanced performance features for those prioritising energy efficiency.
Rehau Flush
Positioning: Premium
Overview:
Rehau’s Rio Flush Fit windows offer a modern interpretation of the traditional timber flush casement window. Designed with attention to detail, these windows provide a minimalist impact on a property’s exterior while delivering high performance.
Key features:
- Design options: Available with both chamfered and sculptured frames, the Rio Flush Fit windows can suit any installation, whether traditional or contemporary.
- Jointing methods:
- Fully welded: For a seamless finish.
- Full mechanical joint: For an authentic timber appearance.
- Mechanical/weld combination: Offers flush aesthetics outside and a standard finish inside.
- Energy efficiency: The windows are ‘A’ energy rated with a thermal performance of 1.3 W/m²K, contributing to a comfortable living environment and reduced energy costs.
- Customisation: Rehau offers a range of hardware and colour options, allowing homeowners to personalise their windows.
- Compatibility: The Rio range is compatible with Rehau’s existing systems, making it better for those making these windows.
Why choose Rehau?
Rehau’s Rio Flush Fit windows suit homeowners seeking a customisable window with various jointing options for tailored aesthetics. Their commitment to energy efficiency and design flexibility makes them a strong contender in the mid-level market. The Turner Oak finish on these windows is beautiful.
Kommerling Flush
Positioning: Mid-level
Overview:
Kommerling’s 76 double-seal flush casement windows are designed to offer heritage aesthetics with modern performance. They provide an authentic timber look, both inside and out, and are packed with features that appeal to homeowners seeking traditional design without compromising on efficiency.
Key features:
- Flush design inside and out: The windows are flush on both sides, providing a clean and uniform appearance reminiscent of traditional timber windows.
- Heritage features: Includes traditional butt joints, dedicated face-fix Georgian bars, and period-inspired finishes like English Oak and Painswick.
- Energy efficiency: Designed for double and triple glazing up to 48mm, these windows offer outstanding thermal performance, helping reduce heating costs.
- Centre seal option: An optional centre seal enhances weatherproofing against wind and rain, contributing to the window’s durability.
- Hardware choices: Homeowners can select from traditional hardware options like tear-drop or monkey-tail handles in various finishes, adding to the window’s authentic appearance.
- Colour options: A wide range of foiled finishes are available, including both traditional and contemporary colours, with dual-colour options for interior and exterior customisation.
Why choose Kommerling?
Kommerling’s flush windows are ideal for those seeking a true period window design with modern benefits. Their attention to detail in replicating heritage features and high-performance credentials make them a compelling choice for traditional properties.
Profile 22 Flush
Positioning: Mid-level
Overview:
Profile 22’s Flush Casement Window system is designed to replicate the original features of timber casement windows more accurately than many rival products. They offer superior thermal performance and a range of options that make them suitable for heritage projects.
Key features:
- Authentic design elements:
- Mechanical jointing: Allows for the replication of traditional timber joints.
- Deep bottom rail option: Enhances the authentic timber appearance.
- Dummy sash: Provides a balanced look across the window.
- Energy efficiency: Achieves U-values of 1.4 W/m²K or better with double glazing, contributing to energy savings.
- Customisation:
- Colour options: Includes period colours and dual colours to match interior and exterior decor.
- Hardware: Authentic hardware options like monkey-tail handles and dummy peg stays enhance the traditional look.
- Installation benefits: The system uses standard Profile 22 outer frames and packers, making it easier for installers to work with variations in older properties.
- Additional features: An extensive range of cills, bay poles, and accessories are available to complete any project.
Why choose Profile 22 Flush?
Profile 22’s flush windows are a solid choice for homeowners seeking authentic timber aesthetics with modern performance. The system’s flexibility and installer-friendly features suit many properties, especially those requiring heritage considerations.
Joints and Corners on uPVC flush sash windows
Welded, mechanical or timber look. These are the three offerings on flush casement and timber-look PVCu windows. Most brands give you an option. And it’s the choice of corners that make these windows stand out. Rehau and Residence 9 does it best in our view. The timber-like joint on these windows is the most appealing joint as it stops the product from looking like a regular plastic window. Go for the timber-like mechanical joint wherever possible.
The corner images below are courtesy of Rehau with the Rio window, which looks gorgeous in the Turner Oak Finish.
Styles and aesthetics of flush windows
You have a wide choice of profile styles to choose from to suit the architecture of your property. You can keep the modern contemporary look with clean lines and large panes of glass or go down the more traditional cottage style by adding Georgian bars.
The door furniture choices will also change the style from traditional black handles and window peg stays to hold open the windows to give them an authentic look to a modern, clean look with chrome handles.
Why is there a black line between the outer frame and the window of my uPVC flush windows?
The black line will be the gasket, known as a shadow gap, which forms a weathertight seal between the window elements; in the raised uPVC windows, this gasket is hidden within the frame.
Products at a higher price point may have a less prominent black line or non-existent. This shadow line and black gasket is essential for the performance of the window. White gaskets are avoided as they look dated, dirty and ineffective very quickly.
Making the Right Choice
With a variety of high-quality options available, choosing the right flush window involves considering several factors:
- Aesthetics and authenticity:
- Exterior vs interior flush: Decide whether you prefer windows that are flush on the outside with a decorative interior (like Evolution’s offerings) or flush on both sides (like Residence 7 and Kommerling).
- Traditional vs contemporary: Consider whether your property style leans towards traditional heritage or modern minimalist, as some brands cater more specifically to one or the other.
- Customisation options:
- Colours and finishes: Look for brands that offer the colours and finishes that match your property’s aesthetic.
- Hardware choices: Authentic hardware can enhance the traditional look, while modern hardware may suit contemporary homes.
- Performance requirements:
- Energy efficiency: Check the U-values and energy ratings. Brands like Liniar and Deceuninck offer windows with U-values as low as 1.2 W/m²K.
- Weatherproofing: Features like double-rebated seals (Liniar’s Resurgence) or optional centre seals (Kommerling) can enhance weather performance.
- Security: Ensure the windows come with robust locking mechanisms and meet relevant British and European standards.
- Budget considerations:
- Premium vs mid-Level: Evolution and Residence Collection are positioned at the luxury end, offering the most authentic timber-like appearance. Mid-level brands like Liniar, Deceuninck, and Rehau provide excellent quality with different pricing structures.
- Installation quality:
- Professional fitting: Regardless of the brand, proper installation is crucial for optimal performance and longevity. Ensure that your installer is experienced with the specific window system you choose.
Pros and cons of flush uPVC windows
What are the advantages of uPVC flush windows?
- Chosen well, it is an excellent alternative to timber windows.
- The timber-look and flush design is best with uPVC.
- The textured foils and woodgrains are of excellent quality and authentic-looking close-up.
- The timber-look uPVC flush windows have less maintenance than real wood windows.
What are the disadvantages of uPVC flush windows?
- The top-end brands can be as expensive as some aluminium windows.
- The black gasket that peaks out on some models between the outer frame and opening elements may not suit everyone’s aesthetic style and looks most prominent on white or light-coloured windows.
- There is no slimline version.
- All windows have dummy sashes in fixed panels, meaning more material and a higher price than regular windows.
Some brands may also have a matching door to go with the windows. We think doors are not as aesthetically pretty as the windows and quite bulky. There is no rule that you must have the same materials and brands across the whole property. The expert opinion of this website is that the most reliable long-term doors are never uPVC doors. Aluminium residential, timber, and hybrid doors last longer and perform better.
Reassurance and quality on uPVC flush windows
There are no inherently “bad” uPVC flush windows. All the brands, thankfully, have excellent standards to adhere to or exceed. uPVC profile quality, glass, gaskets, hardware, and foils are similar. All are tested to the latest weather and security tests and meet or exceed building regulations for U-values and thermal performance. The differences often lie in the following:
- Aesthetic details: Variations in sightlines, jointing methods, and design elements can influence the window’s appearance.
- Material and engineering: The quality of the uPVC profiles, foils, and finishes can vary between brands, as can the design and engineering.
- Hardware and components: Higher-end brands may offer more premium hardware options.
- Brand perception: Luxury brands like Evolution and Residence Collection are perceived as offering more authentic and high-end products.
- Supply chain and manufacturing: The reliability of the supply chain and manufacturing processes can affect product consistency and availability.
- Installation quality: The skill and experience of the installer play a significant role in the window’s performance and longevity.
A correctly made and professionally installed window should provide reliable service long-term. The key is to find the right balance between aesthetics, performance, and budget that suits your specific needs, with the right products from the proper, expert suppliers. This is where we can help.
Are uPVC flush windows expensive?
uPVC flush windows are more costly than the older style raised profiled uPVC windows but cheaper than wood or aluminium.
Which are the best uPVC flush windows to buy?
| Brand | Description | Price Guide |
| Evolution Windows | The Original and in our view one of the very best flush casement windows and timber look products. Designed and manufactured in the UK, these started the trend and remain a fantastic choice and recommended. |  |
| Residence Collection | The Residence collection of windows comprising R9, R7 and R2, are simply gorgeous. With first-class quality, attention to detail and visibly luxurious, these do not look like plastic windows. Ensure the windows come glazed from the factory and not glazed on site. Balanced, symmetrical and beautiful. |  |
| Liniar | Liniar in Derbyshire has one of the UK’s largest uPVC extrusion manufacturing sites. Linair’s 70mm flush sash window has a choice of mechanical or welded joints. The 80mm Flush Sash Resurgance’s design eliminates the unsightly visible black gasket due to a double rebated seal, which means the sash is sealed on both sides and sits flush in a groove in the window frame. |  |
| Deceuninck | Profile 22 is a leading British uPVC company renowned for manufacturing high-quality window and door systems. It includes their innovative Flush Casement Window that combines traditional timber aesthetics with modern energy efficiency and security features. | |
| Rehau | The Residence collection of windows comprising R9, R7 and R2 are simply gorgeous. With first-class quality, attention to detail and visibly luxurious, these do not look like plastic windows. Ensure the windows come glazed from the factory and not glazed on site. Balanced, symmetrical and beautiful. | |
| Profile 22 | Rehau is in our view one of the better PVCu companies with an excellent reputation of profile quality design and price point. The flush collection is attractive, funcdtional and with lovely joint options with Turner Oak being beautiful. |  |
| Kommerling | Kommerling is a renowned uPVC company celebrated for its advanced window and door systems, notably their 76 double seal flush casement windows that seamlessly blend traditional heritage aesthetics with cutting-edge performance and exceptional energy efficiency. | |
More information and where to buy uPVC flush windows
Selecting the right uPVC flush windows is a significant investment that can enhance your home’s appearance, energy efficiency, and security. Whether restoring a heritage property or upgrading a modern home, there’s a flush window option to meet your requirements. The advice is always to see the products in a showroom or up close.
Need further advice?
We at DWE understand that choosing new uPVC flush windows may be daunting because the various brands and installers provide the product information in different forms. We provide product advice and put you in touch with the best products from the proper suppliers. We are impartial, independent, and expert.
If you would like some personal help regarding your project, please get in touch with us, we will be happy to help.
