The ECM Motor: How It Boosts Your HVAC System's Energy Efficiency

ECMs are more efficient for several reasons:

• ECMs can be used at fixed speeds or variable speeds, however, ECMs installed in air-handler systems are usually variable-speed motors. In both applications, ECMs are more efficient because of their superior technology. For instance, variable-speed motors allow the manufacturer to have a great deal of flexibility in the operation of the blower. The motor, when used in an air handler or furnace blower, uses the exact amount of energy necessary to emit the required warm air. Since standard fans run almost all the time and have only one speed, standard fans can use as much as 75 percent more energy to heat the home. However, ECMs installed in single-speed applications are also much more efficient than PSC motors.
• ECM  motors run on Direct Current, making them cheaper to run. Alternating Current goes into the motor, and then it is converted to Direct Current using a rectifier.
• A soft start and soft stop feature programmed by the manufacturer also contributes to efficiency. When the blower comes on, it will not start out at 100 percent, but instead starts lower. After a certain amount of time, it will increase to 100 percent. When the temperature is at a certain point, according to the thermostat, the blower will slow down before stopping completely.

ECMs are also much quieter than PSCs, another benefit of these newer motors.

All of these features combine to create a motor that is energy efficient at all speeds. In fact, ECMs can save up to three-fourths of the power that was required by the older motors.

For more information about these new and more efficient motors and how they might help you increase energy efficiency, contact Rodenhiser Plumbing, Heating & Air Conditioning for assistance.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information about ECM motors and other HVAC topics, download our free Home Comfort Solutions Guide.