Influence of building airtightness on the internal thermal comfort and air quality in the single family house

The knowledge of the air exchange and building air-tightness is an indispensable source of information, both on the design and operation stage of the building use. Properly functioning ventilation system affects significantly internal thermal comfort and internal air quality. Infiltration of air determines the proper functioning of the gravitational ventilation, still the most commonly used system in Polish single-family housing. However, the most popular and easy to measure parameter: building airtightness (n₅₀), does not specify the real air exchange in the actual climatic conditions. The real air flow rate may be determined with much more troublesome gas tracing method. Air flow rate, n, is in this method obtained from the decaying curve of gas concentration after injection of tracer gas into the building. This paper presents the results of the airtightness measurements conducted in a single family house with natural ventilation. Both, n₅₀ parameter and building air flow rate n have been measured. The results of the measurements were used as a model calibration tool in the annual computational simulations carried out in the Design Builder program for the Polish climatic conditions. Based on these simulations the authors determined the influence of building airtightness on the internal thermal comfort and the potential scenario of its control.