The regulation of a country can represent a big obstacle for the application of Fuel Cell microCHPs. For this reason, an analysis of the Italian regulation for the building energy efficiency is carried on. The main objective of this study is to find possible obstacles to the diffusion of SOFC microCHP systems and to understand if the higher electrical efficiency of these machines is considered in a positive way for the calculation of the energy demand and energy class of a commercial building. In the first part, the Italian regulation is analysed, with a focus on the methods for the evaluation of the energy consumption of the building and on the constraints imposed by the Ministerial Decrees.