The European directive 2002/91 imposed the energy certification of buildings that serves to give the user an identification of the energy quality of the building. The energy classes range from A + to G. In the Lombardy region, this activity started in September 2007 thanks to CENED. C.en.ed (or rather Buildings Energy Certification) is a portal dedicated to the energy certification of buildings. By accessing it, it is possible to consult the legislation, choose the certifier, proceed to accredit the certifier, view the certification and the statistical data. To access all these services, you must log in to the CENED portal and register.