Acta Scientiarum Polonorum

In Poland, natural ventilation is the most popular method of ventilating rooms, including premises in residential
buildings. This type of ventilation works under the influence of the forces of nature due to the pressure
difference between the external air and the inside air, as a result of which natural ventilation is difficult to
control and predict the correctness of its functioning. Natural ventilation works best in winter when there is
a large temperature difference and on windy days, when the wind speed exceeds 3 m·s–1, while the worst
in terms of efficiency of natural ventilation is the spring–autumn transition period. In order to improve the
effectiveness of ventilation chimney pot is used, which is designed to improve the chimney effect. The efficiency
of ventilation determines the demand for ventilation air in rooms. The efficiency of natural ventilation
(ACH) is determined based on the dependence in which it is necessary to estimate the amount of air leaving
the ventilation system in relation to the volume of the ventilated room. The article presents the influence of
the chimney pot on the efficiency of gravitational ventilation through the determined ACH values. The work
uses the results from field tests carried out in the existing building.