Rationel Windows & Doors in Surrey, Hampshire & Berkshire

Rationel specialises in bespoke high-performance aluminium clad and timber windows and doors crafted from long-lasting, sustainable materials for commercial and residential properties.

As a pioneer of innovation, design and quality, Rationel is one of the leading window and door brands in Europe for low energy buildings and Passive House construction.

Each year they design and manufacture thousands of bespoke low or no maintenance architectural glazing solutions through a trained, authorised network of distributors in Denmark, Ireland and England.

The first Rationel timber window was developed in 1954 by a highly skilled carpenter in Denmark. In 1999 the company joined the VKR Group. They became part of the DOVISTA Group when it was established in 2004. (A sister company to Velux)

With over 60 years of experience in the Danish window and door market, they have gained a wealth of expertise and knowledge in the energy efficiency of double and triple glazed windows and doors.

Rationel has grown globally driven by its entrepreneurial vision and commitment to constant product innovation and development to ensure its industry-leading range of windows and doors remain at the technological forefront to meet the requirement of every new build, refurbishment extension or large commercial project.

With exceptional heritage and a tradition that started over six decades ago in Denmark, Rationel is synonymous with their iconic Scandinavian window and door design and maintain a reputation for superior craftsmanship and quality design with the most exemplary attention to detail.

They continually invest in the latest manufacturing technology to produce high-performance windows and doors in their state-of-the-art factory by highly skilled technicians that meet European and UK regulations and standards (including ‘Secured by Design’)

Why Choose Rationel Windows and Doors?

Rationel specialises in Scandinavian architectural glazing design to maximise natural light and meet the highest standard of weather tightness, security and comfort.

With a head office based in UK, Ireland and Denmark, they have grown to become a reliable and trusted company and a leading manufacturer of aluminium clad and timber windows and doors.

Every window and door are expertly crafted using traditional techniques and manufactured using premium sustainable materials; this ensures the highest possible specification and provides an excellent lifespan of their windows and doors.

Traditional or Contemporary

Sleek and minimalist clean lines lie at the heart of Scandinavian window design to ensure breath-taking aesthetics.

Rationel offers two timber window collections, AURA and FORMA, depending on your architectural requirements. The difference with the PLUS collection is the material of external aluminium cladding to create high-quality composite windows.


The AURA range delivers an elegant timber solution offering all the beauty and warmth of a natural wood finish both internally and externally.

Aura windows and doors are crafted with responsibly sourced, coniferous timber from sustainable forests offering low maintenance, enhanced durability and performance to ensure a superior lifespan.

Aura offers outstanding architectural elegance; their sleek, minimalist design provides a contemporary look that is hard to rival. Large glazed areas ensure a stunning level of clarity and allow maximum natural daylight and solar heat gain for a pleasant modern living environment.


The Aur Plus range is at the forefront for outstanding energy saving, durability, and unmatched aesthetics through a combination of design, technology and engineering.

Timber composite windows are crafted from multiple layers of laminated wood, with a durable exterior powder-coated aluminium cladding that provides a sleek outside finish and protects the windows against severe weather conditions and requires zero maintenance. – no sanding, staining or painting is required!

Both AURA and AURA PLUS offer a variety of different window styles and openings and an array of colours. To enhance the architectural elegance of the property, they provide optional glazing bars.

AURA and AURA PLUS can easily achieve the Passivhaus energy efficiency standard, reducing your energy bills and CO2 emissions.


Traditional flush timber windows designed for the 21st century to complement British architecture

The FORMA range is a timeless collection of timber windows. Wood is a natural, sustainable and renewable material with endless design capability for bespoke shaped windows.

Forma windows provide a traditional look with modern performance and optional glazing bars.

The ovolo-moulded profile and angled glazing bead replicate the authentic features of original timber windows.

They are perfect for country-style home renovation projects for period properties.

The FORMAPLUS timber range offers new freedom in architectural design. The superior technical performance and superior thermal insulation set new standards.

FORMAPLUS is designed with external aluminium cladding attached with clips, ensuring minimum maintenance. This product range is ideal for a new build if a classic expression is desired.

Why Choose Thames Valley Windows

We work with homeowners, self-builders, developers, and architects to provide the finest Scandinavian timber and aluminium-clad windows and doors for UK projects.

We offer a variety of energy-efficient window ranges from different manufacturers

When you’re looking for a reliable, trustworthy company to fit and supply your Rationel windows and doors, you can be confident that Thames Valley Windows is the ideal choice.

With over three decades of experience in the glazing industry, we are a long-established family company who put our customers at the heart of everything we do. Your satisfaction is our main priority, and that is borne out by our Trustpilot 5-star rating.

Our wide range of glazing solutions for home renovations, new builds and industrial offices extends from traditional and heritage timber sliding sash windows, bespoke aluminium entrance doors to modern and contemporary flat roof lights, glass lanterns, sliding and bi-folding doors and steel-look room dividers

You can depend on our experienced and trained fitters to carry out all aspects of the work on your project professionally and efficiently, so you are guaranteed an impressive final result, and if you need advice or guidance when it comes to choosing the right product to suit your home or preferences, you can rely on our knowledgeable team who can point you in the right direction.

As one of just 33 UK companies to have been awarded a BSi kitemark for quality surveys and installations, we offer exemplary service, and the 10-year guarantee which is supplied on all our products will bring you extra peace of mind.

Thames Valley Windows aims to take all of the worry and stress out of choosing new window and doors solutions for your home, and thanks to our impressive range, you are sure to find something that is perfect for your needs.

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