Energy certification is mandatory for commercial and services buildings, public buildings, among others. The optimization of energy use in companies plays an important role in their competitiveness and an important environmental gain. Through energy certification, we characterize the installation and the main energy consuming equipment. We identify opportunities to reduce consumption, either by replacing equipment or by changing processes. Prosegur is a global reference company in the private security sector and provides businesses and homes with reliable security based on the most advanced solutions on the market. Prosegur entrusted DELAB – JesusFerreira Consultores with the renewal of the Energy Certification of its headquarters buildings, located in Lisbon, with approximately 4 000 m2 and in Porto, with approximately 3 500 m2, of useful floor areas.