Rationel FORMA ensures that high levels of daylight and solar heat gain are achieved. This free heat is the best energy source available and also provides a healthy and comfortable indoor climate. These windows come with security ironmongery as standard, and are suitable for Passiv Haus buildings. With high performance triple-glazing or double-glazing, FORMA windows achieve U values as low as 0.78, which is ideal for low energy buildings and Passive House construction.
Rationel FORMA & FORMA+ come with security hardware as standard to meet SBD requirements. The vast majority of timber originates from FSC-certified forests.
Windows With Vision
Good, solid, quality workmanship has characterised Rationel’s windows and doors since the first products were shipped from our factory in Sdr. Felding in 1954. Based on this sound foundation, Rationel is today an international company with sales offices in Great Britain, Ireland and Denmark. Rationel manufactures energy saving windows and doors of premium quality in terms of both comfort and security. Our continuous programme of research and development ensures that the company always meets current statutory requirements as well as market requirements for design and functionality.
Rationel is part of the DOVISTA Group, which consists of ten leading door and window companies in Europe. DOVISTA A/S is owned by VKR Holding and employs approximately 13,500 people in more than 40 countries.