To calculate the thermal value Uw (window + glass), the Psi value is a value to be considered. This depends on the type of insulating glass spacer and window frame. The Psi value is also influenced by whether it is double or triple insulating glass.
In the thermal calculation, the insulating glass spacer is of essential importance, especially with a large proportion of frames.
Architects and designers must prove that the glass element meets the standards or special requirements (SIA 380/1, MINERGIE, MINERGIE P, EnFK).