Ventilation is much more than opening a window when air is subjectively experienced as bad. With ventilation, smells, warmth, CO2 and humidity are meant to be removed to foster one’s wellbeing. As soon as the development of the interior space is addressed, planners put much time and effort into the elaboration of an individual ventilation concept for their project. However, at this stage it is too late. Building ventilation already Begins during the façade construction period – to be concise, while choosing suitable windows. With the use of louvre windows, planners regulate sophisticated building ventilation in the early design phase. The Stockstadt am Main-based company HAHN Lamellenfenster GmbH has played a pioneering role in this respective field since the 1950s. With such longstanding experience in innovative, natural ventilation systems, they are the right contact to tell us about the many advantages of louvre Windows.