If a thermostat detects that the temperature is too cool, it typically responds by activating the heating system to raise the temperature back to the desired setpoint. Thermostats function as regulating devices that sense the temperature of a system and then switch heating or cooling devices on or off to maintain the temperature near a setpoint

. For example, in a home heating system, if the room temperature drops below the thermostat's set temperature, the thermostat will turn on the furnace or heater until the temperature reaches the set level, then it will turn off the heating. In some specific thermostats, such as those with low temperature protection functions, if the temperature falls below a certain threshold (e.g., 5°C), the thermostat may automatically start and set the fan speed to high to protect the system or environment, switching off once the temperature rises again

. In summary, when it gets too cool, a thermostat activates heating or other warming mechanisms to restore the temperature to the desired level, ensuring comfort or system protection