New definition for high-efficiency furnaces


New standards from U.S. Department of Energy (DOE) are now in effect for fans in residential furnaces.

What is an electronically commutated motor (ECM)?
ECMs are motors that vary the capacity at which a furnace fan runs. They don’t have an on/off switch, meaning they can slowly ramp up and down as needed. This saves energy by allowing the furnace to operate at a partial load. Many homes have furnaces sized to meet maximum heating needs, but they often don’t need to operate at full capacity.

In contrast, permanent split capacitors (PSCs) cannot vary capacity, resulting in furnaces that are prone to short-cycling, which can reduce the equipment’s overall lifespan and efficiency.

New federal requirements
PSC motors have been the dominant option for the last decade, but in recent years ECMs have become more affordable. As a result, the USDOE created a rule to move the market to similar high-efficiency furnace fan motors in 2014. As of July 3, 2019, manufacturers must follow the new standards. These standards necessitate that most residential furnace fans/air handlers incorporate either ECMs or X13 motors. USDOE expects the change in motor standards to reduce furnace fan energy consumption by as much as 46 percent. The official ruling is available online.

Impacts on builders
The ruling impacts manufacturers but does not stipulate point-of-sale requirements for retailers or distributors. Builders should be aware that vendors will likely phase out their stock of non-compliant motors over the next several months. Energy Trust of Oregon is monitoring uptake of compliant motors within the EPS New Construction offering and, in the future, the code baseline will likely include ECMs to reflect this broader rule.

This is great news for consumers looking to buy new homes. More efficient furnaces will boost the energy efficiency of homes, leading to greater energy savings and comfort, and a lower EPS.

Work with the EPS New Construction team and your rater/verifier to start incorporating ECMs into your designs and receive support with other energy-saving opportunities. For more information, contact the trade ally hotline at 1.877.283.0698.