In comparison Ug values of conventional windows often are around 2 W/m²K. The total solar energy transmittance (g value) of triple-glazed Internorm windows lies at about 50% depending on the coating and the gas filling. Using these window systems in central Europe in south-facing houses with little shade the heat gain is greater than the heat loss even between December and February. However, besides the glazing the insulation of the window frames as well as the thermal bridges of the glass edge and the connecting area window to wall need to be considered; otherwise any positive heat gain would be cancelled out immediately.

Average window frames have an Uf value of between 1.4 and 2.2 W/m²K – this means the loss would be twice as high as if super glazing was used for the same surface. In comparison to that the frame of an Internorm window with fixed glazing for example reaches an incredible Uf value of between 1.4 and 2.2 W/m²K.