A blower motor drives the fan in a furnace or air handler that pushes household air across the heat exchanger or evaporator coil and through the ductwork. Older equipment uses permanent split capacitor (PSC) motors with fixed speeds, while newer equipment uses electronically commutated motors (ECMs), which adjust speed and use less electricity.
Why it matters to you
If the blower stops, a furnace can overheat and an air conditioner can freeze its coil, even while the burners or compressor keep running.
Practical guidance
Squealing, humming with no airflow or a burning smell mean turning the system off and having the motor and its capacitor tested. A clean filter and open vents reduce strain on the motor.