This article summarizes the results of a survey on ventilation system types in some EU countries. The survey was performed with a questionnaire that was sent to various EU experts on ventilation. They used the official statistic data to fill-out the questionnaires or their expertise if the former is not available. The responses from the participating countries showed that national official statistics of ventilation systems is not available from any country. The results show that in all countries the use of natural ventilation systems is decreasing in favour of mechanical ventilation systems. The evolution is different in all counties but the trend is the similar. The distribution of ventilation systems has had a similar evolution from natural ventilation systems towards mechanical ventilation systems. The evolution occurred sooner for some countries than others but it is clear that lately mechanical ventilation practises are forced by emerging regulations regarding energy efficiency and performance. But still, as most houses from the building stock are old houses the overall distribution of ventilation systems allocates the greatest share to natural ventilation systems.