What factor chiefly affects airflow in an HVAC system?

The chief factor affecting airflow in an HVAC system is duct size and configuration. The ducts in an HVAC system are responsible for transporting heated or cooled air throughout the building. The size of the ducts directly correlates with the volume of air that can flow through them; larger ducts allow more air to pass, while smaller ducts restrict airflow.

Additionally, the configuration of the ducts, including bends, turns, and fittings, can significantly impact how easily air flows through the system. Sharp turns and constrictions can create turbulence and resistance, obstructing the smooth flow of air.

In contrast, while duct material can influence factors like insulation and resistance to wear, it is primarily the size and configuration that determine how effectively air can move through the system. Thermostat settings and seasonal temperature changes affect the demand for heating or cooling but do not inherently change the physical characteristics of airflow through the ductwork.