Abstract: In a building, electric storage heaters (204) receive off peak electricity, generate thermal energy and store this thermal energy for later release. Each storage heater has a local control device (201) for controlling thermal energy generated during the reception of the off peak electricity. Each local control device receives a generation schedule from a building control device (207). Each building control device controls many local control devices and transmits information to a central control device (208). The central control device transmits generation schedules to many building control devices. Each schedule is constructed in response to room related data supplied by the local control devices, building related data supplied by the building control devices and regional data supplied to the central control device.