Improving the energy efficiency of the thermal conditioning of buildings is an international priority. Along this line, there have been major advances in the insulation of enclosures and the equipping of facilities. The need for building ventilation has an enormous impact on the environmental energy consumption evaluation. Filtration resulting from imperfections in enclosures and partitions always accompanies narrow ventilation flow, increasing the unabated consumption of energy. The present research study establishes an evaluation procedure for this excess energy consumption via an experimental study carried out in various buildings located in the north and central part of Spain. The procedure, commonly called the Blower Door Test, is based on standards EN 13829 and ISO 9972. The work is composed of the following sections: a description of the air entry processes in buildings, an experimental study and calculation of the airtightness of enclosures, a discussion of the energetic effects of infiltration and conclusions.
