Run to success

Rationel FORMA and FORMAPLUS Window

Key Features

Typical LifespanFORMA: 60 years
FORMAPLUS: 85 years
Lead Time8-10 weeks from sign off
Best U-Value0.78 W/m^2k
Finishes Any RAL Colour
for both timber and aluminium (FORMAPLUS only)
GlazingDouble, Triple, Obscure, Solar, Toughened
Performance and
Air Permeability: 600 PA
Wind Resistance: 1600 PA
Operation: 10,000 cycles
Water Tightness: 600 PA
Manufactured inPoland

Further Details:

Holding more than 60 years experience, Rationel employs 1,050 people in Denmark, England, Ireland and Poland; manufacturing premium quality, durable and stylish windows and doors.

Designed for a more traditional style of building, the Rationel FORMA window has an all-timber construction with slim, non-continuous bars. Featuring an ovolo moulded profile and angled glazing bead, FORMA is perfect for older, classic and country style houses.

In terms of timber construction, the Rationel FORMAPLUS window is identical to FORMA. The only difference between them is the addition of external aluminium cladding included on the FORMAPLUS window. This inclusion ensures both minimum and easy maintenance characteristics.

Both products have a wide variety of opening designs, glazing options and configurations. Along with the typical styles, Rationel FORMA and FORMAPLUS can be manufactured in bespoke shapes to correspond to an assortment of openings. Featuring fully adjustable and secure ironmongery (Secure by Design part Q compliant hardware), two gaskets and the option of trickle vents; FORMA and FORMAPLUS are carefully engineered with the customer in mind. Furthermore, all Rationel products prioritise energy efficiency. The slim design naturally takes advantage of the solar heat from daylight, and the exceptional insulating qualities reduce CO2 emissions significantly.

Due to their energy efficient characteristics, both Rationel FORMA and FORMAPLUS are suitable for Passiv Haus buildings.

Thanks to constantly enhancing efficiency and optimising the products, Rationel windows are designed to withstand all weather types, attempted break-ins, and finally the constant wear and tear of repeatedly opening and closing windows year after year.

“We basically offer a complete service. For over 60 years our company has been based on excellent craftsmanship. This is still the case. At Rationel we take a pride in delivering high quality,” Rationel CEO Thomas Tvedergaard Larsen.