The requirement for a ventilation concept under DIN 1946-6 is meant to clarify fundamental questions about ventilating a building or usage unit. Changes to the building envelope result in changes to the ventilation of the rooms inside it, which is why a standardized ventilation concept must be created for every new build as well as for extensive renovations of existing buildings. For existing buildings, a ventilation concept is required when more than 1/3 of a residential unit’s existing windows are replaced, or when more than 1/3 of the roof area of a single-family home is newly sealed. The planner must determine, from a hygiene and building-protection standpoint, how the necessary air exchange can take place. We are happy to assist you with this task.