Residential Plumbing & HVAC Experts

Your Furnace Replacement: All About the ECM

A furnace ECM (electronically commutated motor) runs longer and performs better, yet consumes up to 75 percent less energy than a standard permanent split capacitor (PSC) motor. An ECM is a brushless blower motor with fully controllable speed and torque. The blower portion of the furnace is a major contributor to the electrical consumption of your heating system. Yet, blowers are not figured into the energy-efficiency ratings published by the furnace manufacturer. Therefore, a new higher-efficiency furnace mated with a conventional PSC blower motor may not live up to those improved efficiency specs. Here’s what’s different about a furnace ECM:

  • ECM technology is programmed to operate at variable speeds. Unlike a PSC blower that is either on or off, an ECM blower ramps up gradually to full output. Once the thermostat setting is achieved, it slows to incrementally lower outputs, eventually coming to a “soft stop.” Averaged over all speed ranges, a furnace ECM consumes about as much electricity as an 80-watt light bulb.
  • Variable speeds heat more evenly and avert the abrupt temperature fluctuations of conventional “on/off” blower operation.
  • Since output during most of the blower cycle is at substantially less than 100 percent, motor noise is reduced, as is the sound of air flow in the ductwork.
  • ECM technology reduces maintenance requirements and minimizes stress on the blower motor. More continuous, low-speed operation inflicts less wear and tear than abrupt, repetitive starts and stops.
  • Healthy air quality requires continuous circulation through the system air filter. During a PSC blower’s frequent “off” cycles, filtration ceases and airborne particulates may accumulate and settle. Since ECM blowers run extended “on” cycles at lower output, circulation and filtration are sustained and indoor air quality improved.
  • Until Dec. 31, 2013, a federal tax credit will refund $50 on the cost of including ECM technology in your furnace upgrade.

Sherlock Air Conditioning & Heating has the solution to the home comfort needs of San Diego area residents. Ask us for still more clues to the advantages of upgrading to a furnace ECM.