The EMS observes, live, how much energy the building is consuming. Within a meeting room, occupancy, door (open / close) humidity and temperature sensors are installed to watch and learn. With the technology list above installed, now watch what happens. People leave the meeting room and leave the AC on. The door sensor knows the door has been opened and then closed, which then speaks to the occupancy sensors, who says "there has been no movement within the room for the last 5 minutes".
The humidity and temperature sensors know that the room is at a temperature of 16c, even though outside its 21c (hence why the AC is on), the sensors within the room then send a signal to the control unit, which is connected to the AC, which then switches off the AC, remotely, without any human intervention at all.
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