CSLB Class B General Contractor's License Practice Exam

Which of the following best defines the function of a thermostat in an HVAC system?

1. To regulate humidity levels

2. To monitor and maintain temperature

3. To manage air filtration

4. To control air flow rates

The correct answer is: To monitor and maintain temperature

The function of a thermostat in an HVAC (Heating, Ventilation, and Air Conditioning) system primarily revolves around monitoring and maintaining temperature. A thermostat is designed to sense the ambient temperature in a space and compare it to a preset temperature that the user desires for comfort. When the ambient temperature deviates from this set point, the thermostat sends signals to the HVAC system to either activate heating or cooling, thereby ensuring that the indoor environment remains at the desired temperature. This control mechanism is crucial for energy efficiency as well, as it prevents unnecessary heating or cooling when the desired temperature has already been achieved. By continually monitoring the temperature and making adjustments as needed, the thermostat enhances comfort and energy usage, ensuring that systems operate optimally without excessive energy expenditure. While regulating humidity levels, managing air filtration, and controlling airflow rates are important functions within an HVAC system, these tasks are typically handled by other components or systems. Humidity control often involves a humidistat, air filtration is managed by filters within the HVAC system, and airflow rates are generally controlled by dampers and fans, rather than the thermostat itself. Therefore, the primary function of the thermostat is indeed to monitor and maintain temperature.