How Variable-Speed Blower Motors Enhance Energy Efficiency And Comfort

Rarely seen but very important, the blower motor in your furnace, air conditioner or heat pump influences not only overall system efficiency but home comfort as well. Blower motors provide the air flow within the heating or cooling system, controlling how quickly and effectively conditioned air is moved from the unit, into the ductwork, and into your home from vents and registers. Highly efficient HVAC systems have better air flow from using variable-speed blower motors.

Many older HVAC units contain permanent split capacitor (PSC) motors in the unit’s blower. These motors are inexpensive, but they are inefficient since they run at only one speed, switching on and off as temperatures change in your house. Newer heat pumps are often equipped with ECM, or electronically commutated motors. ECM motors operate at variable speeds depending on the temperature demands of your home.

Variable-speed blower motors perform more consistently than other motors because they operate only at the speed that's needed to maintain a constant airflow. They usually run at about 2/3 speed at the start; if the thermostat still requires heating or cooling after 10 minutes, they increase to full speed. This allows variable-speed motors to run more often at lower levels, improving efficiency, making indoor temperatures more consistent, and reducing wear on the motor and fan.

ECM motors use up to 60 percent less electricity during normal operation. They do not waste as much energy during high-demand times. In general, ECM motors can save up to 20 percent on energy costs over a comparable PSC motor. ECM motors are also quieter than PSC types. When run continuously to increase indoor air circulation and filtration, ECM-equipped fans and blowers consume only about as much energy as a 100-watt light bulb. This can amount to as much as a 90 percent savings over the cost of running a standard blower motor for air filtration.

Since 1976, Comfort Services and Total Comfort Service Center have provided residential and commercial heating and air conditioning services to customers in Columbia and the surrounding area. Contact us today for information on home heating maintenance or to schedule an inspection or service call.