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Why Rationel Windows are a good choice – 13/07/2017


Are looking at purchasing some new windows? Need some independent guidance from a company that are not tied to one manufacturer?

In this blog, we look at why Rationel windows are a good choice of product for replacement windows or new build.

Click Here for the Rationel Gallery

Who are Rationel Windows?

rationel windows

Rationel Windows are a Danish Window manufacturer who only sell their products via approved distributors. This means that members of the public cannot purchase the product direct from the factory or the UK offices. Rationel are a sister company to Velux.

Rationel have a UK office and also provide a comprehensive UK guarantee.

What Do They Make?

Rationel manufacture both composite (low maintenance on the exterior timber) and timber-only windows and doors, which are made in automotive style factories using high tech machinery. All windows and doors are made to measure with a lead time of 6-10 weeks from confirmed order, depending on the time of year (please check with us for exact timings).

Rationel manufacture windows using good quality materials and, consequently, can be considered in the mid-range price bracket from the products offered by Enlightened Windows.

The key ranges are:

Aura and AuraPlus, which are timber only and timber alu windows respectively. The AuraPlus window is effectively the same as the Aura window in section, but has a low maintenance aluminium exterior – available in many RAL colours and, when purchased via Enlightened Windows, granite colours at no extra cost.

Aura and AuraPlus are particularly suited to modern style buildings and have a flush exterior appearance. The brochure can be found here.

Rationel Aura

Forma and FormaPlus are again timber and timber alu products respectively, and are particularly suited to more traditional style buildings. These feature an angled and curved external glazing bead, and a chamfered internal glazing bead. There is also the option for a very slim 25mm glazing bar (commonly known as Georgian bar) often found in traditional properties.

Download the Forma and FormaPlus brochure for more information.

Rationel Forma

Since the windows are all made to measure, they can be made in a wide range of standard colours at no extra charge.

The product is available in double or triple glazed options with a wide range of glass for safety and also for solar heat protection.

Product Tests

Rationel test all ranges to the standards below.

Wind Resistance

Firstly, Rationel windows and doors are suitable for even the most extreme wind forces, and the company regularly tests the product construction to the wind force of a hurricane. These, thankfully, are not conditions seen regularly in the UK but, rest assured, the product is fit for purpose.

The windows are tested to both positive and negative pressures of 2400 pascals.

Unlike many manufacturers, who try to manipulate results by testing only a fixed window, Rational test an double opener.

In the video below, you can see the physical wind resistance test is performed.

Water Tightness

In addition, with UK weather extremes regularly coming into the news, it is important that you carefully future-proof your window and door purchase.

In the video below, the test exposes the window to a wind speed of 27 metres per second and moderate(!) rain in the form of 600 L of water.


The window didn’t leak.

Wear and Tear

Many windows sold in the UK suffer from poor quality manufacture and poor quality components. All of the products we sell are extensively tested: ensuring that we would be happy to put these into our own homes.

Windows and doors are opened and closed many thousand times during their life. So quality hardware within the window is critical to ensure that the opening sash remains tight to the window. Most UK sold windows have no adjustment in the hinges and fittings but, with Rational windows, most components are adjustable. So, if a window starts to stick slightly, it can be rectified.

For more information, see the Operation and Maintenance Manual we provide with every purchase.

During the test below, a custom-built machine performs an open and close test. The machine opens, closes and rotates the handle repeatedly for 14 days in 20,000 opening cycles. The window passed the test due to its durable construction.


Finally, a key feature and reason for choosing Rationel Windows is the improvements in security. We are able to offer any of the above products in Secure by Design (secure by design is an official police security initiative) and, in the test below, observe a 15 minute break-in test – performed using 8 different tools.

Want more information? You can receive a copy of any of the Rationel product catalogues direct to your door. Please fill out the from below to receive a copy of the Rationel Aura/AuraPlus, Forma/FormaPlus and/or doors brochure.


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Rationel Aura/AuraPlusRationel Forma/FormaPlusRationel Doors

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