Optimization of air tightness and night ventilation for Passive houses in Italian climates under Fanger and Adaptive comfort models

The IEE Passive-on project has drafted a proposal to adapt the Standard to the conditions that characterize Southern Europe. Compared with the original definition, one of the main changes is the introduction of explicit requirements on internal comfort during summer, in parallel to a limit to energy needs for cooling. The dynamic simulations conducted to test the new definition of the Standard in the context of Southern Italy (e.g. Palermo) show that the requirements identified by the Standard Passivhaus can be met by simplifying the envelope technologies (e.g with a lower level of air-tightness compared to the northern version) and adopting passive cooling strategies (e.g. night ventilation) appropriately adjusted. Some ventilation plant simplifications can be compensated by an increased role of thermal insulation and some of the choices can make energy needs tend to zero.