Final answer:
The term related to the temperature difference between the thermostat's activation and the stop of warm air delivery is thermal equilibrium, indicating that the room has reached the set temperature.
Step-by-step explanation:
The temperature difference between the opening of the thermostat and when the warm air is no longer delivered to the room is related to the concept of thermal equilibrium. This is the condition in which heat no longer flows between two objects or environments because they have reached the same temperature. In the context of heating a room, once the room air reaches the temperature set on the thermostat, heat delivery stops, indicating that thermal equilibrium has been achieved. Factors such as insulation, heat transfer, and air infiltration influence how quickly thermal equilibrium is reached and how effectively it is maintained.