Abstract
This paper proposes a new methodology of determining the building heat losses associated with natural and (or) forced air ventilation, based on continuous measurements of the temperature, humidity and carbon dioxide concentration in the air. Determining the flow rate of infiltrating air is performed by the active and passive experimental methods. The proposed method allows determining the exact amount of heat losses associated with ventilation or infiltration of the building under environmental conditions. In addition, the paper proposes an algorithm of calculating the actual number of people present in the room and the associated heat gains based on the air composition analysis. The proposed methods can be used as tools for conducting energy inspections of buildings and structures, as well as be part of effective building energy supply management systems.