Ventilation systems for windows Controlled and deliberate ventilation is continuously growing in importance due to the fact that the building shell becomes tighter as a result of more and more stringent thermal and energy efficiency requirements. This Guideline lays down the methods to determine the materials-neutral performance characteristics of ventilation systems for windows. It applies to decentralised ventilation elements which are integrated in the window or which are directly connected to the window (ventilation systems for windows, fans), e.g.: air transfer devices and/or internal air transfer openings, ventilation systems for window sills, add-on elements, ventilation systems for window rebates, hardware controlled ventilation systems, fan-assisted ventilation devices, with or without heat recovery, with manual, automatic or sensor control.weiterlesen