This certificate must be issued by a qualified technician, the Energy Certification, which briefly describing the energy behavior of the building or building unit allows you to classify it according to the performance indices that take into account the efficiency of the heating system, the production hot water, air conditioning in summer, and the use of renewable energy sources. The certificate of Energy Certification is mandatory for new buildings to existing buildings is required in the event of sale or lease and to gain access to tax deductions related to energy conservation. It is also necessary in case you wish to advertise a property for the purposes mentioned above.