Thermal insulation energy efficiency tests have been carried out at the IFT Rosenheim Rosenheim. It is indicatively noted that the Uw coefficient for a I.V. 68 series window carrying 4-15-4 double glazing, is 2,4 W/m²K.
Thermal insulation laboratory test results are summarized below:
The thermal insulation (energy efficiency) of windows is expressed by the thermal transmittance coefficient Uw. The Uw expresses the amount of thermal energy that is lost through a given window system and is measured in Watt per window surface per temperature (W/m2K).
A respective thermal coefficient also exists for glazing (Ug).