This paper illustrates the results of a research focused on the development of a multi-scale geodatabase designed to store the data needed to measure the energy buildings performance of buildings to be used for the planning activities of local administrations. Due to the great complexity of the application domain, the proposed data model has been structured in three main components: the building/heating system, the users, and the environmental/territorial context. Furthermore the characteristics of these components and of their mutual relationships have led to the decision to use geometries in the 3D space. The applications also need a significant semantic content, expandable with customized elements and properties. These peculiarities directed us to select the OGC CityGML standard format as the best choice for the data model. This choice has been tested with positive results.