Tag Archives: Electronically Commutated Motors

Electronically Commutated Motors: are ECMs worth it?

There seem to be many ways to save energy in home heaters and air handlers. Recently I’ve been hearing about “ECM” motors in these appliances. What are they are and are they worth any extra expense?

There are many ways that manufacturers are increasing the energy efficiency of their products. You’ve probably seen the Energy Star rating on new appliances. Since 1992, the Federal government has been giving tax incentives and rebates to manufacturers and/or consumers for making improvements like reducing the amount of water needed to wash a load of towels or the amount of electricity needed to run your refrigerator.

One of the ways of accomplishing energy use reduction is by using electronically commutated motors (ECM). The construction of these ECMs allows the motor to run at different speeds, depending on the demand from the appliance. This type of motor has been in use in the US since 1985 and uses as much as 67% less power than that used by standard motors (PSC). That’s because sensors in the motor determine the need of the system and provide just the amount of energy needed. ECM motors are also quieter and cooler than standard motors.

A simple system that uses ECMs these days is a home hot water distribution system such as radiant-heat floors. The ECM runs the pump which distributes the hot water to heat your rooms. A sensor in the system measures the temperature of the fluid in your system and tells the pump to run only as fast as it needs to to heat your rooms.  When run most efficiently, your system using an ECM could use less power than a standard light bulb.

HRVs (heat recovery ventilation systems) are also now made with ECMs. Just as with the hot water circulator pump, the HRV’s motor will vary its speed (and therefore energy use) based on the demands from the building. When you push your “booster” button in the kitchen, the motor will run the fan at a faster rate and exchange more air for a set period of time. When the HRV is operating at its normal (lower) level, it will use less power and run less forcefully.

While it is possible to have a professional retrofit your current furnace, HRV or other appliance with an ECM motor, it is generally more cost-efficient in the long run t to purchase a new appliance. Some appliances are not configured to allow the conversion at all – the older it is, the more this is likely.