Airtightness in Spanish Residential Buildings. Case Study

The control of the airtightness is a key factor to reduce the buildings energy demand. The present document describes the development of a predictive algorithm to estimate the airtightness of new or renovated buildings. The study is based on the results of almost 300 blower-door tests made in different dwellings and buildings with diverse envelope configurations and geometries. Two different analysis were made, the first one interrelates seven different parameters from an algorithm specifically designed for that purpose. Then, a second analysis from an energy efficiency point of view were made, evaluating the numerical results obtained, valuating the physical correlations of these results, defining the risk threshold for each case, categorizing the different alternatives and defining the conclusions of the study. Among other advantages, the predictive algorithm allows to evaluate, before assuming any investment, the risk that the company should fulfil to reach the different standards demanded by the clients. Besides, based on the test results, this algorithm let determine, in an early stage, what design or constructive changes need to be done to reach the specific airtightness demanded. This research demonstrates the relevance that the quality of workmanship must obtain an airtight building or dwelling. Besides, it is highlighted the influence that the choice of the materials and constructive solutions have on the level of air infiltration.