To meet the increasingly stringent requirements of standard energy consumption and thus reducing operating costs of buildings, it is necessary to use energy-saving elements of technical equipment and eliminate heat loss through the building envelope. The biggest losses are caused by heat transmission and ventilation in the form of uncontrolled air infiltration through the building envelope. Their elimination can be achieved by improving the thermal technical quantification of building envelope and increase its airtightness. Determination of air permeability as a measure of quality building envelope is possible using the method of measuring devices Blower-Door test. Any defects can be detected by detection tools, then propose a suitable method for their removal and thus prevent unwanted unregulated air infiltration into the interior. On the other hand, are opposed to the health requirements required air exchange in the room, which is a significant reason for the transformation of this mode of ventilation by uncontrolled air infiltration to a controllable ventilation system. The subject of the paper is in-situ measurement of air permeability of specific apartment envelope by Blower-Door test method and comparison the efficacy of the installed controlled ventilation system and hygiene requirements of the ventilation intensity for residential buildings. Laboratory verification of façade ventilation unit parameters in big pressure chamber - measurement of inlet ventilation flap airflows at variable pressure differences. Methodology for the measurement by Blower-Door test method to determine the air permeability of building envelope structures and functionality of controlled ventilation system was based on a series of 10 measurements in 5 regimes. The overall air permeability of the building envelope or its integrated part may be verified using the total air exchange rate n50at 50 Pa pressure difference, determined experimentally according to STN EN 13829. Comparison of measured values with standard values recommended by some European countries with a similar climate with sealed and with unsealed ventilation flaps, which can determine the impact on the overall airtightness of the building envelope. Calculation of total hygiene required air exchange rate of the apartment and its comparison with actual measured values by Blower-Door test method.