What is the difference between AC, DC, and EC fans?

AC fans run on alternating current (110V/220V) — simple, reliable, fixed speed, lower cost. Best for: HVAC, industrial ventilation where speed control is not critical. DC fans run on direct current (12V/24V/48V) — compact, speed-controllable via PWM or voltage. Best for: electronics cooling, servers, telecom. EC (Electronically Commutated) fans combine AC input with DC motor efficiency — 30-50% more energy efficient than AC, built-in speed control, quieter. Best for: air purifiers, FFU, energy-conscious HVAC, refrigeration.