The Eco mode is used for saving energy. When Eco mode is enabled,  the temperature setpoint is raised and the light is switched off. Eco mode can be enabled by pressing the button on the front of the controller or automatically. For automatic Eco mode, you must mount a light or motion sensor or a door sensor. If the light sensor is used, the Eco mode will be enabled or disabled according to the ambient light level (e.g. shop lights). The motion and door sensor can also be used to enable or disable the Eco mode. When there is no movement for some time (sensor or door), Eco mode is enabled. Movement will disable the function again.