The module allows you to calculate Sw solar factor, which is an indicator of the gains of the transferred solar heat by the window construction into the room.This value relies on several factors. First of all, it depends on thermal insulation parameters of both the whole structure (Uw value) and the glass itself. The greater the amount of solar heat passed, the higher the value of Sw factor is. Just as important is the colour of profiles used in the window construction. The darker they are, the faster they heat up under the influence of solar radiation, and the more heat is transferred.The window design with the high Sw factor satisfies the condition of applicability for passive heating buildings. The module is useful primarily for manufacturers of windows who export their products or have their retail outlets throughout the European Union.