Air tightness measurements of residential houses in Athens, Greece

During summer 2005, regular air tightness and infiltration measurements were performed in 20 houses, in the area of Attica, Greece. Two measurement methods were used, the tracer gas decay method and the Blower Door tests method. Blower Door measurements were done in accordance with EN ISO 13829 [Hellenic Standard “Thermal performance of buildings—determination of air permeability of buildings—fan pressurization method”]. Ambient conditions and temperature fluctuations inside the houses were measured as well.The average number of air changes per hour (ACH) was approximately 0.6 ACH, when tracer gas method was used, while the average number of ACH at a 50 Pa pressure was 7 ACH, when the Blower Door tests method was used.A classification of houses examined, based on experiments’ results was acted out in accordance with EN ISO 13790 [former 832. “Thermal performance of buildings—calculation of energy use for heating”]. The houses were classified into three air tightness categories, in regard to their air tightness in natural conditions and at a pressure difference of 50 Pa.A statistical homogeneity test between regression coefficients of Blower Door measurements is performed for each category of air tightness. The sample of buildings that belong to the “low air tightness level” category are statistically homogeneous, while the samples of buildings that belong to the “medium” and “high” air tightness level are statistically uneven.Finally, the total frame length was estimated for the whole housing stock, and a correlation between the air tightness measurements at a pressure difference of 50 Pa and the total frame length was examined, for the sample of buildings and for each air tightness category. The correlation coefficient R2 has the greater values at the “low air tightness” category.