Buildings play a major role in energy expenditure, representing 40% of Europe's total energy consumption. It is estimated that heating, ventilation, and air conditioning systems consume between 50-60% of the total energy spent inside the building, thus corresponding to 20% of global worldwide energy consumption. Hence, there is a need to improve the accuracy of building thermal simulation and energy models that are essential in regulatory compliance calculations. In the present study, the authors empirically validate an optimization-based calibration methodology based on its application to a fully operational commercial building located in Pamplona, Navarre. The methodology used a white-box two-stage model in EnergyPlus, which combines a load profile object and a district cooling component to distribute the cooling load inside the building's thermal zones. The study optimized the parameters and performance curves of different cooling system components using a second-generation non-sorting genetic algorithm in jEPlus software and 985 h of ten-minute time-step data. Finally, a multi-level benchmark is executed, which evaluates the electric energy consumption of the building's heat pumps and the interior temperature of the different thermal zones for summer 2020 conditions. The assessment of the thermal and energy performance of the simulation model was conducted according to the requirements of the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Guideline 14-2002, and the Chartered Institution of Building Services Engineers, Operation Performance Technical Memoranda 63.