Glossary · Heating, cooling & ventilation
ECM (variable-speed) blower motor
Also called: ECM motor · electronically commutated motor · brushless DC motor · variable-speed blower
A high-efficiency, variable-speed fan motor for furnaces, air handlers and HRVs that uses far less electricity than older motors, especially at low speed.
What it means
Older furnaces use permanent split capacitor (PSC) motors, which run at about 60%–65% efficiency at full speed and less when slowed down. An electronically commutated motor (ECM, also called a brushless DC motor) stays near 80% efficient even at reduced speed, so the furnace fan can circulate ventilation air or filter smoke cheaply. NRCan says a brushless DC motor can cut average furnace electricity use by more than 70% when the fan runs continuously.
Why it matters in an audit
If you run the furnace fan to spread HRV air or filter wildfire smoke, an ECM motor keeps that from adding a big electricity cost.
Typical numbers
Reference values with their sources. Your energy advisor’s report gives the figure for your own house.
| What | Value | Source |
|---|---|---|
| Motor efficiency (NRCan) | PSC motors 60%–65% at peak; ECM motors near 80% even at reduced speed | natural-resources.canada.ca ↗ |
| Continuous circulation (NRCan) | More than 70% less furnace electricity with a brushless DC motor | publications.gc.ca ↗ |
| Canadian furnace rules | New gas furnaces must also meet a fan energy rating limit | natural-resources.canada.ca ↗ |