A method for detecting the opening of an access door to a climate-controlled room, wherein the temperature inside the room (1) is measured by means of an ambient temperature sensor (5), the measured temperature (Ts) is processed by means of a plurality of parallel calculation processes (12-15), each of which generates an open door event (ET, ED, EI, ETAV) when a respective event condition occurs, and the opening of the door (2) is signalled as soon as any of the parallel processes (12-15) generates an open door event (ET, ED, EI, ETAV).
