s it possible to build Passive Houses, i.e. dwellings which can be kept within the comfort range simply by heating, cooling, and/or dehumidifying the supply air, in the climates of Portugal, Spain, Italy and Southern France? What would be the properties of such buildings, and would they be an appropriate solution for these climates at all? This book analyses 12 selected locations in the Mediterranean using dynamic thermal simulation for a typical two-storey end-of-terrace house with 120 m² of living area, south orientation and moderate window areas. The key findings are: humidity levels play an important role for summer comfort in many locations. Hygrothermal processes were therefore explicitly considered, both in the simulation and in the evaluation of the resulting data, which sometimes leads to fundamentally different results.