What does an HVAC system primarily use to control indoor temperature?

The primary method that an HVAC system utilizes to control indoor temperature is through thermostat settings and zone control. A thermostat is a critical component that monitors the indoor temperature and communicates with the HVAC system to adjust heating or cooling outputs to reach and maintain the desired set temperature.

Zone control refers to the ability of the HVAC system to heat or cool different areas (or zones) of a building independently. This allows for customized comfort levels in various spaces, catering to varying needs and preferences based on usage patterns, occupancy, and even specific areas that may require more or less heating or cooling.

While humidity levels do play a significant role in overall comfort and may influence temperature perception, they are not the primary means by which HVAC systems adjust indoor temperature. Similarly, while the type of refrigerant is essential for the operation of cooling systems, it does not independently control indoor temperature. Lastly, building materials can affect a structure's thermal performance and energy efficiency, but they do not actively control temperature in the way that thermostat settings and zone control do.