Infiltration plays a relevant role regarding the energy performance of buildings. Many European countries have already established standards which aim to limit the energy waste through the envelope following the European Energy Performance of Buildings Directive guidelines. However, in Mediterranean countries there is still a lack of knowledge in this field. An extensive study has been carried out in order to characterize the air leakage through the envelope of the existing housing stock in the Continental climate area of Spain. Results of 129 dwellings tested, including different typologies and periods of construction, are shown. Blower door tests were performed, and thermal imaging was used to locate leakage paths. Single-family dwellings were found to be more airtight than apartments, given that the mean air permeability rate at 50 Pa (q50) was 5.4 m3/h·m2 and 6.8 m3/h·m2 respectively. The mean air change rate at 50 Pa (n50) was 6.1 h−1 for single-family dwellings and 7.1 h−1 for multi-family housing. Nevertheless, great dispersion of results and extreme values were found. In addition, the influence of several construction characteristics on permeability results was assessed. •Pressurization tests were performed in 129 dwellings in the Spanish Continental area.•The mean ACH50 was 7.1 h−1 for apartments and 6.1 h−1 for single-family dwellings.•No relationship was found between construction features and permeability results.•Leakage places were located in windows, shutters, ducts and construction joints.