The blower motor is the fan motor that pushes conditioned air through your ductwork. It’s the single most-used component in your HVAC system — it runs whenever the furnace or AC runs, plus any time you set the thermostat fan to “on” or “circulate.”
PSC vs. ECM — the major distinction
- PSC (Permanent Split Capacitor) — older single-speed technology. Found in 10+ year old furnaces. Draws 400-700 watts at full speed, can’t run at low speed.
- ECM (Electronically Commutated Motor) — modern variable-speed. Found in mid-tier and premium furnaces from 2014+. Draws 60-200 watts at low speed, ramps up smoothly. Quieter, more efficient, longer cycle times.
If your furnace was installed in the last 10 years and is a mid-tier or higher model, it almost certainly has an ECM blower. The energy and comfort difference vs. an old PSC is dramatic — running the fan in “circulate” mode is essentially free with ECM, prohibitive with PSC.
Common blower issues
- Failed capacitor (PSC motors) — no startup
- Bearing wear — loud noise or wobble
- ECM control module failure — won’t ramp up properly
- Belt slippage on older belt-drive blowers (rare in residential)
Related: CFM, Static Pressure, Capacitor.
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Right Way Mechanical is a family-owned HVAC contractor serving Wheat Ridge, Arvada, west Denver, and the Colorado foothills.