What is the primary input for a thermostat?

The primary input for a thermostat is temperature readings of the environment. Thermostats are designed to monitor and regulate the temperature in a space to maintain a desired comfort level. They achieve this by taking regular measurements of the ambient temperature and comparing it to the setpoint defined by the user.

When the temperature deviates from this setpoint, the thermostat signals the heating or cooling system to either heat or cool the air until the desired temperature is reached. While humidity levels, airflow measurements, and pressure levels can play important roles in climate control and comfort, the core function of a thermostat primarily revolves around temperature monitoring and control. Thus, the correct selection reflects the central role temperature plays in the operation of a thermostat.