Eco-technologies for energy efficient buildings in Italy

The climatic context has an essential role in the building construction strategy: it represents the main benchmark to define criteria for energy-efficient buildings design. The control of external conditions through the building envelopment is essential for energy saving. Environmental protection and energy saving characterize some strategic European experiences. Lots of European countries are promoting and sharing a sustainable building approach to be in compliance with the Kyoto Protocol and subsequent international agreements, such as those established at the last Copenhagen climate conference. Assuming that buildings have a high environmental impact, in terms of energy and resources consumed, it is necessary to adopt different criteria in relation to climate zones. The design strategies in terms of new constructions and upgrading of existing buildings are based on the concept that building is a composite system, where the architecture, the layout of fronts and openings, the performances of the building shell and integration with the fixtures and fittings, also powered by renewable sources, must be efficiently balanced. The Passivhaus standard, which defines low energy buildings with heating not dependent on fossil fuel, was originally developed in central European countries and recently it has been revised to adapt its criteria to different climate contexts, especially those of the Mediterranean. In warm areas the energy efficiency is related to summer performances and passive cooling of buildings. Significant experiences are developing even in Italy, where the Mediterranean climate has different characteristics compared to the cold climates of central and northern Europe. Italian regions have more differentiated climates: according to the seasons, protection from summer heat and energy containment during the winter have differing levels of importance. In southern and central Italy the main factor is the heat control in the summer period, during which situations of overheating – which imply relevant energy consumption due to conditioning systems – shall be limited. It is possible that the energy required to cool the buildings exceeds the requirements for heating.