This paper emphasizes the importance of environmental protection regarding the reduction of energy consumption while maintaining living standards. The aim of the research is to observe the effects of mechanical and natural ventilation on energy consumption and building operation as well as indoor environmental quality (IEQ). The results of indoor environmental quality testing show that the mean relative humidity (31%) is in the permissible range (30%-70%); the mean CO2 concentration (1050.5 ppm) is above the recommended value of 1000 ppm according to Pettenkofer; and the mean PM10 concentration (43.5 µg/m3) is under the limit value of 50 µg/m3. A very large positive correlation is found between relative humidity and concentration of CO2 as well as between the concentration of PM5 and the concentration of CO2. The most commonly occurring sick building syndrome (SBS) symptoms are found to be fatigue and the feeling of a heavy head.
Keywords: CO2; IEQ; PM; SBS symptoms; energy performance; historical building; mechanical ventilation; natural ventilation.