The energetic understanding of medieval buildings requires a joint study, because in this building typology, the structure acts as a climatic protection as is known. From another point of view, medieval buildings tend to be grouped in a pineapple, conditioning the climatic and structural understanding. Therefore, the knowledge and study of the old urban models is crucial for their understanding. The urban model and its surroundings determine the climatic demands of the interior spaces. In the same way the construction characteristics and materials. The article aims to develop an open system of hydrothermal measurements that allows hydrothermal comprehension of spaces. The result will be a sensor system with interpretable data that will allow us to understand the hydrothermal system of a medieval building located in its context. The interpretation of these data will allow making a comparison between different construction solutions that allow improving the hydrothermal conditions of the interior according to the climate.