For decades, the permanent split capacitor (PSC) motor dominated the residential HVAC market, powering furnaces and air conditioners. However, advancements in technology and regulations have introduced new options for HVAC motors. Electronically commutated motors (ECM) are now gaining market share, offering increased efficiency and reduced costs for homeowners. For technicians, stocking ECMs can save time and boost profits. The Genteq® Evergreen® motor is an industry-leading ECM that can replace millions of PSC motors, benefitting homeowners and technicians alike.

About Permanent Split Capacitor Motors

PSC motors are single-phase AC motors with a permanently connected capacitor. They deliver high horsepower with a low starting current but have a limited speed range. In HVAC applications, PSCs power outdoor condensers, indoor air handlers, furnaces, variable air volume systems, and other equipment.

Despite being more than a century old, PSC technology remains prevalent in the field. While OEMs rarely use PSCs in new equipment, technicians will continue to encounter them for another ten to 15 years.

About Electronically Commutated Motors

ECM technology has been around for more than 30 years. These permanent magnet motors have onboard controls that convert AC line voltage to a DC bus voltage and then back into a simulated AC signal to drive the motor. An internal computer regulates speed, torque, or airflow based on application needs.

ECMs can operate at various speeds and torques, adapting to specific outputs and load demands while maintaining high energy efficiency. For homeowners, ECMs provide constant airflow, enhancing indoor comfort.

Common residential HVAC applications for ECMs include indoor and outdoor HVAC systems, furnaces, condenser units, rooftop units, and kitchen ventilation.

PSC vs. ECM in Residential HVAC

In 2019, the U.S. Department of Energy adopted the Fan Energy Rating (FER) regulation, setting standards for the electrical efficiency of fossil fuel applications in new equipment. FER required furnace manufacturers to reduce fan electrical consumption by 40 percent, potentially saving consumers over $9 billion in energy costs by 2030. This regulation led to a shift towards ECMs in new HVAC systems, although PSCs remain available as replacement equipment.

Advantages of ECMs over PSCs

For consumers, ECMs have many advantages over PSCs. Here are some of the larger differences:

• Comfort: ECMs provide constant airflow and humidity control.
• Energy Efficiency: ECMs use less power than PSCs, which consume 100% of their power when activated.
• Speed Range: ECMs operate efficiently across a full range of speeds.
• Indoor Air Quality: ECMs enable continuous air circulation through system filters, improving air quality and preventing condensation from blowing back into the indoor space.
• Static Pressure Changes: ECMs optimize system performance by maintaining consistent airflow despite static pressure variations like clogged filters.

ECM Benefits for HVAC Professionals

ECMs offer numerous benefits for technicians and HVAC professionals. The primary advantage is simplicity. One ECM motor can replace many PSC motors, streamlining ordering and freeing up space on service trucks. This reduces on-truck inventory and allows technicians to complete more calls without needing to retrieve parts.

Evergreen Motors by Genteq enable technicians to replace millions of PSC motors in residential HVAC equipment with just three ECM motors. For more information on the benefits of Evergreen Electronically Commutated Motors and training options, visit HVACmotorsolutions.com or download the HVAC Motor Solutions app.