The energy certification of buildings is there? was introduced in Italy in 2005 by Legislative Decree 192 and implemented in full with l’ issued, in June 2009, by the National Guidelines on Energy Certification of the Edi ci (DM June 26, 2009). The certification is intended to inform the 26-member user / purchaser of a property about the performance and energy characteristics of the property itself. So every building and every single unit? real estate must bring a ’ ” label” with l’ indication of one's energy ef ciency class. Just like already? for household appliances, this certification is intended to promote the dissemination of high quality standards from the energy point of view and allows the user to make an informed choice. L’ energy performance certificate must be drawn up by a qualified professional in compliance with the rules imposed by the region of competence and by the National Law and is it valid? 10 years from its release. The 26-rsquo; certificate indicates the energy class to which the 26-rsquo; belongs, and the possible improvements that could increase l&ef ciency. The National and Regional Laws on the 26-energy efficiency of the buildings prescribe limits to be respected and objectives to be achieved that are different depending on the level of intervention on buildings. For new buildings or buildings that have undergone major renovations, a good overall energy performance (low energy demand) is required. For partial interventions it is required to adopt technologies (casing or plant) such as to guarantee good performance to the components subject to intervention.
The parameter that expresses the level of isolation of a structure è the thermal transmittance U (W / m2K), which expresses the 26-rsquo; ability of a structure to transmit the fl ow of heat. This è one of the parameters on which the 26-rsquo energy efficiency regulations in force set a limit: in the event of intervention on opaque structures of existing buildings, the post-intervention fi nal transmittance must be più low by a certain limit value. This value varies depending on the climate zone in which the 26-rdquo building is located. The Italian territory è divided into 6 climatic zones from A (più warm) to F (più cold): so più l’ building is located in a cold climatic zone, so much moreù the transmittance limit sarà low, ie&level; dovrà be increased l’ thermal insulation.