Energy efficiency in buildings is of particular importance in the pursuit of international objectives in the area of climate and energy, as it is a sector that represents approximately 40% of the total primary energy demand [1], with strong growth prospects in absolute consumption. In Portugal, the implementation of the Energy Certification System and Indoor Air Quality (SCE) [2] [3] [4] is an important step in the promotion of energy efficiency and achievement of the national targets regarding the emission of greenhouse gases. This work presents the application of the SCE system to a large office building, the Lisbon City Hall. In the context of the energy audit that was performed, different energy optimization scenarios were defined and analyzed in a cost-benefit perspective. Emphasis is placed on the calibration of the building thermal simulation model (EnergyPlus [5]) and its results. Based on this application of an energy certification code, an examination of the principles that underlie these systems is performed, resulting in a qualitative reflection on the limitations of the SCE system and opportunities for its improvement
