What component in an HVAC system is primarily responsible for controlling airflow?

The blower motor is the component in an HVAC system primarily responsible for controlling airflow. This motor drives the fans that circulate air through the ductwork of the system, ensuring that heated or cooled air is effectively distributed throughout the space. The blower motor's speed and operation can be adjusted to control the volume of air moving through the system, which is critical for maintaining comfortable indoor temperatures and airflow.

In the context of the other components: the condenser plays a role in cooling by removing heat from the refrigerant, the heat exchanger transfers heat between two fluids (in both heating and cooling operations), and the thermostat is a control device that regulates the system based on the desired temperature setting, but none of these directly manage or propel airflow like the blower motor does.