The aim of every project is to use energy in the best possible way to reduce the environmental impact, to avoid waste and to obtain the right quality of thermal and hygrometric comfort within buildings. To understand the potential of renewable sources one only needs to understand that the total solar energy that reaches the earth is approximately ten thousand times higher than that currently utilized by mankind as a whole. Being fully aware of the difficulty in capturing all this potential at our present state of development, humankind has also devoted itself to harvesting other kind of renewable resources, like that generated by wind, water and geothermal sources and the product of transformation into electrical energy of plants and organic, and inorganic, waste.

Energy efficiency is the ability of any building ecosystem, and not only, to take advantage of energy sources to achieve the desired result, bearing in mind that the lower the consumption the higher the efficiency of the system. Consumption savings allow a cost reduction while achieving the same result through the use of advanced materials and technologies. The application of new methods of construction can only derive from a careful and conscious initial design that relates the building to the nature of the context in which it is inserted, to its specific characteristics, and to the intrinsic limits of the existing structure. Specialized knowledge of the materials used and their combination with renewable energy sources is the only way forward for sustainable development.

Energy redevelopment comprises all the technological and managerial operations that contribute to improving the energy efficiency of existing buildings, such as:

• Improving the comfort of indoor environments;
• Reducing energy consumption;
• Reducing the energy flows between the building system (casing and systems) and the external environment;
• Reducing hazardous pollutant emissions and their impact on the environment;
• Rational use of resources through the replacement of fossil fuels with renewable energy sources;
• Optimizing the energy services management.

The 2010 European Directive 2010/31/EU (EPBD – Energy Performance Building Directive) introduced the concept of “almost zero energy” for public and private buildings, the so-called Nearly Zero Energy Building (NZEB), which is considered a world benchmark for construction and building refurbishment. This means energy-efficient buildings that minimize the consumption of heating, cooling, ventilation, lighting, hot water production, renewable energy use, passive heating and cooling elements, shading systems, and ensure a proper indoor air quality plus adequate natural lighting in accordance with the architectural features of the building. An interdisciplinary design meeting these requirements can only be accomplished by a team capable of producing and managing every specific aspect mentioned above.