In order to reach energy efficiency at any level, the importance of the human factor has to be acknowledged. On one hand, efficient solutions (regarding, for example, building energy consumptions) have to be implemented by an authority who understands the complexity of the urban context and its impacts on the environment; on the other hand, it is important to improve citizens’ awareness of their environmental impact and to lead them to use available solutions to their full potential. In the field of residential use of energy, people are therefore a crucial parameter of both the problem and its solution. The EPC has been designed by authorities to “provide clear information about the energy performance of a building”, in order to influence the real-estate market, promote energy performance improvements and help build up comprehensive benchmarking databases, fundamental for shaping strategies on a local or regional level. The EPC, however, offers in return of a 200€ visit, results that are often too distant from reality and difficult to understand for the lay person. “Consumers do not understand CO2 or kWh”. They do not understand “primary energy” either, given that their only knowledge of their energy consumption are the final energy bills. The procedure might be necessary, but the general picture shows a great opportunity remaining underexploited, a potential driver to reducing energy consumption and CO2 emissions, surrounded by barriers and obstacles that render its use all the more difficult. While appreciating the necessity of presenting a “legal” result as a comparison base, following the approved standardized calculation method, it is believed that the input data used in the quasi-steady state calculation method could be used to display complementary results. Additional data on the household’s composition, their practices and behaviours related to energy consumption, as well as a more accurate search in the description of the energy system, could help close the gap between real and theoretical consumptions, ...