The paper presents airtightness measurements results of the multi-family building. The tests were carried out in several ways, the results obtained by different methods were compared and the likely reasons for the discrepancy of results were indicated. The object of measurements was a six storey building with 47 dwellings equipped with natural ventilation. Air inlet to the rooms through the window trickle vents controlled by relative humidity of air. Air is extracted through vertical extract ducts made of ceramic blocks.
The measurement for the whole building was carried out twice: with open and manually closed trickle vents. Additionally, the airtightness of each dwelling was measured. For several exemplary apartments, detailed measurements of airtightness were performed with and without pressure compensation in the adjacent zones.