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. RMR Architects is a Projects, Studies and Consultancy company that develops a wide range of services, operating in all phases of the project and work and that, in this context, used the services of DELAB – JesusFerreira Consultores to carry out the Energy Certification of the Amadora Conforama building, a 9 000 m2 property.