A comfortable indoor climate makes a key contribution to our wellbeing. Thermally insulated windows, doors, façades and fixed glazing consisting of steel profile systems help to save precious energy – the better the thermal insulation, the lower the energy loss through the building’s shell. Thermally insulating buildings is also a legal requirement: on the European level there is the Building Directive from the European Union and in Germany there is the Building Energy Act (GEG 2020).
The objective measure of thermal insulation: the U-value
Heat loss through building parts is expressed by the heat transfer coefficient or U-value. The U-value indicates how much heat escapes to the outside per square metre if the outside temperature is 1°C lower than inside. This loss of heat can be minimised by using thermally insulating steel profile systems. In building parts made up of several components, the U-value can be determined for each individual component as well as for the part as a whole. A letter in subscript after the U denotes the relevant object: For example, a subscript f refers exclusively to the frame whereas a subscript w refers to the window as a whole. Put more simply, the lower the U-value, the greater the thermal insulation.
Daylight helps save energy
To save energy, it is not only essential to prevent heat from escaping from the building shell, but also to maximise the amount of daylight that enters the building. Daylight not only saves electricity but is also a freely available source of light. Because of this, the guiding principles in architecture have changed in recent years. There has been a growing shift away from closed-in, artificial and entirely air-conditioned interiors towards buildings that – without compromising on comfort – require very little energy whilst meeting the demand for greater openness and transparency.