Method for simplified calculation of controlled natural ventilation. As the building envelopes of energy efficient buildings are becoming increasingly air-tight, ventilation concepts are increasing in importance in order to ensure good quality room air and reliably prevent dampness. DIN 1946-6 contains requirements for producing ventilation concepts in housing - for the first time also in order to prevent dampness - which are satisfied by fan-assisted or free ventilation through external openings. An important prerequisite for these ventilation concepts is that they have to be functionally independent of user interaction. For buildings other than housing, DIN EN 13779 contains requirements for ventilation systems regarding the volume of air flow in order to achieve a healthy indoor climate. Furthermore, DIN EN 15251 contains criteria for the thermal interior climate of naturally ventilated buildings.