The Fiemser ontology describes the main classes of the Energy-focused BIM model and WSN-related data that are part of the FIEMSER data model. The ontology describes the building space organization in terms of the Building, BuildingPartition, BuildingSpace and BuildingZone classes. A building partition defines a part of a building managed by either a dweller (e.g., a flat) or a facility manager (e.g., a common building area). A building space defines the physical spaces of the building. A building zone defines a functional area in the building that will be controlled as a unique zone. A building consistsOf some building partitions, a building partition consistsOf some building spaces, a building zone consistsOf some building spaces. The Fiemser ontology also describes the devices (Device class) used in the building in terms of HomeEquipment and ControlledDevice.