This thesis discusses the experimental determination of the effectiveness of the ventilation with pulse method. In the thesis we show area where we perform measurements, measurement equipment and the use of CO2 as tracking gas. We aslo explain procedure of performed measurements by pulse method in isothermic load conditions in two different ways, first by introducing the tracer gas directly into the space and second by introducing the tracing gas in the supply duct ventilation system. On the basis of the obtained results we concluded the usefulness of the both methods and causes of deviation between measurements. We also show how to make necessary calculations for determing the air exchange efficiency and fort his calculations we made Matlab program.