"...an energy audit of the building and of the plant in which you identify interventions to reduce energy expenditure, the times for their investment return, and the possible class improvements in the building energy certification system in force, and depending on which they were established the installation plant choices that are going to be realized" is the definition offered by Annex 1 of Legislative Decree 311/2006.
What are the real benefits of this survey? The Energy Certificate proposes plausible improvements to the building in question. The main difference is in the degree of detail of the investigation, of the reconstruction of the real utilities of the building, of the balance of costs and benefits of each ameliorative case, so as to ensure the effective realization, by the user, of the energy characteristics of the building, its problems, and its potential.
Therefore it becomes an indispensable planning vehicle of restoration and enhancement of a property, or even just a precious detector of reducible operating costs, if interventions for redevelopment are not provided, with the consequent increase of property's market value.