As the existing housing stock ages throughout Europe, retrofitting offers many opportunities for the substantial improvement of the energy performance of residential buildings and the provision of sustainable alternatives to conventional heating and cooling. The effect of global warming is leading to a widespread use of air conditioning in existing and new residential buildings. This potentially implies an increase in cooling energy and adverse environmental effects on an unprecedented scale. In the hot and dry climate of many south European cities, this could be avoided with the use of an innovative wall integrated passive evaporative cooling system, which harnesses air, water and porous ceramic to provide comfortable indoor conditions. Dr Rosa Schiano-Phan discusses the applicability of such a system to the urban context of Seville in the light of the current Spanish regulatory framework and recent developments of European energy performance standards.