The Barcelona City Council manages about 2000 municipal buildings and as expected the energy expenditure is very high. Hence, the objective was to closely monitor and control how these buildings are consuming and, in some cases, producing energy. Specifically, the aim was o determine the degree of utilization of energy produced by solar thermal systems in multifamily buildings. The project consisted on controlling and monitoring 28 solar thermal systems. It was divided into three phases; a pilot phase to monitor 4 initial sites, a second phase where 16 more were added, and a third phase where the final 8 were included.