The European residential building sector accounts for over 40% of final energy consumption in the European Union member states. Therefore, an improvement of buildings energy efficiency represents a great instrument to reduce CO2 emissions. The first step to increase energy performance in buildings is to use passive strategies, such as orientation, natural ventilation or envelope optimisation. This paper presents an analysis of solar passive techniques and natural ventilation concepts in a case study: La Clota residential building, located near Barcelona (Spain). It has been carried out a comparative analysis of La Clota building in order to evaluate its energy and environmental performance with respect to a conventional building and also with respect to another hypothetic building with improved performance with respect to La Clota. Main tools used are energy dynamic simulation and, when necessary, CFD analysis in order to go into the effect of specific measures in depth. Accordingly, conclusions about the most effective energy measures are drawn, not only for this particular building, but also for other Mediterranean climate locations
