ECM Motors: Their Benefits and How They Work
The days of inefficient single-speed, on-off furnace blowers are gone. Many of today’s units utilize multi-speed motors or variable speed blower motors, also known as ECMs (electronically commutated motors). ECMs are more energy efficient than multi-speed motors, require less maintenance, improve indoor air quality, and provide better humidity control. They cost more up front, but they pay for themselves after just a few years.
An electronically commutated motor adjusts its speed in response to changing conditions to maintain a programmed CFM. When a change in torque is sensed, the ECM ramps the RPM up or down to compensate. Different conditions will affect CFM. In cooling mode, a wet evaporator coil will increase static pressure, as will a dirty filter or duct issues. The ECM senses the change in static pressure and increases RPM. Conversely, when there is less moisture on the coil or the dirty filter is replaced, the ECM will decrease RPM. During heating, the ECM will deliver the necessary CFM to maintain temperature and will adjust RPM accordingly.
ECM variable speed blower motors are more energy efficient than PSC (permanent split capacitor) motors, saving about 25% per year on energy costs, and as much as 75% when set to continuous fan mode. The ECM’s ramping capability means quieter operation in comparison to a PSC motor.
About E.P. Homiek
E.P. Homiek Sheet Metal Fabrication & HVAC Supply, with two convenient locations in Lakewood, NJ and Union, NJ, provides one- to two-day turnaround on all residential and light commercial ductwork, as well as one- to two-hour emergency fabrication service, rapid delivery, and competitive prices. HVAC parts, supplies, and equipment lines include Goodman, Honeywell, Bryant, Bradford White, Crown Boiler, Daikin, Weil-McLain, Sea Breeze, Generac, Fantech, ZM, A.O. Smith, Hart & Cooley, Malco, Mueller, and many more.
