The requirements concerning the energy certification of buildings established in Directive 2002/91/EC of the European Parliament and of the Council of 16 December 2002, which was in turn modified by Directive 2010/31/EU of the European Parliament and of the Council, of 19 May 2010, regarding the energy efficiency of buildings, were transposed into Spanish legislation through Royal Decree 47/2007, dated January 19, through which a Basic Procedure for certification was approved of energy efficiency of new buildings, which was consolidated by Royal Decree 235/2013, of April 5, which approves the basic procedure for the certification of the energy efficiency of buildings. In said Royal Decree, it is established that existing buildings or units of buildings occupied by a public authority, must obtain an energy efficiency certificate and will have the obligation to display their energy efficiency label, when their total useful area exceeds 250 m², and are usually frequented by the public. The Basic Procedure is established that must comply with the methodology for calculating the energy efficiency rating, considering those factors that have the greatest impact on their energy consumption, as well as the technical and administrative conditions for the energy efficiency certifications of the buildings. For this purpose, three software programs were promoted from the competent Ministry, one corresponding to the general option (LIDER-CALENER “HULC” unified tool) and two others corresponding to the simplified option (simplified procedures CE3 and CE3X), which allow the energy qualification to be carried out of buildings according to three types of buildings (residential, small and medium-sized tertiary, and large tertiary) that are increasing the requirements of the energy certification of the building depending on the type of the same. This study identifies the possible alternatives for improving energy efficiency over the initial qualification of the building, within a context of technical and economic feasibility, optimizing energy demand, reducing CO₂ emissions and building energy consumption, being The study also compares the results obtained in the energy rating, between the general option and the simplified procedures, on an Andalusian health center in 1957, which corresponds to the typology of the Grand Tertiary building (GT).