Brazil has recorded the biggest hydrological crisis in 91 years, from September 2020 to April 2021. Building automation has been gaining space in recommendations for solutions to improve the energy situation of buildings and residences, as it is a proposal that brings innovation and savings, as well as energy efficiency, comfort and sustainability to the building. In this way, a study of the present energy picture of the School of Technology (EST), of the Amazonas State University (UEA), was conducted, which identified a trend of increased energy consumption during the 2019 school terms, taking into account the lighting and cooling of the building. In addition, it was found that the activation of lighting and cooling is done manually. The results obtained allowed designing a prototype of an energy management system with building automation along with a voice assistant that is responsible for the audible command by the user to the system, thus enabling a more practical control of the classroom lighting and refrigeration. Thus, building automation proved to be an excellent proposal and solution to contribute to the energy efficiency of EST-UEA.