Network for detecting the presence of persons, having a multiplicity of home installation and/or building systems technology devices (3A, 3B, 3C, 3D, 3E, 3F) as network subscribers, having a central processing unit and communication paths between the devices (3A, 3B, 3C, 3D, 3E), • wherein each of these devices (3A, 3B, 3C, 3D, 3E) has an energy supply unit (11A, 11B, 11C, 11D, 11E), a communication unit (12A, 12B, 12C, 12D, 12E), an operating part, a motion detector for switching the lighting system, a first unit, a second unit and a third unit, wherein the network for detecting the presence of persons is characterized in that • the first unit is a flush-mounted tactile sensor and/or a flush-mounted switch, • the flush-mounted switch is a flush-mounted switch for switching a lighting system or a room temperature controller, • the second unit is a brightness sensor or a dimmer switch, • the third unit is a microphone of a door station of a door communication system or a camera of a door communication system, • the central processing unit is provided as a further network subscriber having an energy supply unit and a communication unit, • communication paths are provided between the devices (3A, 3B, 3C, 3D, 3E) and the central processing unit for the purpose of transmitting data signals, • the network subscribers are suitable for communicating with the central processing unit by means of powerline modems (26A, 26B, 26C, 26D, 26E) via the AC voltage power supply, or • the network subscribers are suitable for communicating with the central processing unit by means of bus couplers (28A, 28B, 28C, 28D, 28E, 28F) via the bus system, • the network for detecting the presence of persons is designed such that the devices (3A, 3B, 3C, 3D, 3E) generate data signals and emit them to the processing unit as soon as persons enter the building or particular rooms of the building or persons leave the building or particular rooms of the building, and in that the network for detecting the presence of persons documents the presence of a person at a particular location at a particular time using these data signals, • the processing unit is designed to receive and process the data signals and, by processing the data signals, to simulate the entry of persons to the building or to particular rooms of the building and the leaving of the building or particular rooms of the building by persons, to track the path of persons through the building or to particular rooms of the building and to determine the number of persons in the building. • wherein each of these devices (3A, 3B, 3C, 3D, 3E) has an energy supply unit (11A, 11B, 11C, 11D, 11E), a communication unit (12A, 12B, 12C, 12D, 12E), an operating part, a motion detector for switching the lighting system, a first unit, a second unit and a third unit, • the first unit is a flush-mounted tactile sensor and/or a flush-mounted switch, • the flush-mounted switch is a flush-mounted switch for switching a lighting system or a room temperature controller, • the second unit is a brightness sensor or a dimmer switch, • the third unit is a microphone of a door station of a door communication system or a camera of a door communication system, • the central processing unit is provided as a further network subscriber having an energy supply unit and a communication unit, • communication paths are provided between the devices (3A, 3B, 3C, 3D, 3E) and the central processing unit for the purpose of transmitting data signals, • the network subscribers are suitable for communicating with the central processing unit by means of powerline modems (26A, 26B, 26C, 26D, 26E) via the AC voltage power supply, or • the network subscribers are suitable for communicating with the central processing unit by means of bus couplers (28A, 28B, 28C, 28D, 28E, 28F) via the bus system, • the network for detecting the presence of persons is designed such that the devices (3A, 3B, 3C, 3D, 3E) generate data signals and emit them to the processing unit as soon as persons enter the building or particular rooms of the building or persons leave the building or particular rooms of the building, and in that the network for detecting the presence of persons documents the presence of a person at a particular location at a particular time using these data signals, • the processing unit is designed to receive and process the data signals and, by processing the data signals, to simulate the entry of persons to the building or to particular rooms of the building and the leaving of the building or particular rooms of the building by persons, to track the path of persons through the building or to particular rooms of the building and to determine the number of persons in the building.