What is ECM in HVAC?

Asked By: Bertie Rosedahl | Last Updated: 1st July, 2020
Category: home and garden indoor environmental quality
4.9/5 (111 Views . 43 Votes)
ECM stands for an “electronically commutated motor” which basically means a motor that uses electronic controls to vary its speed. It should be noted that the ECM motor programming is specific to each model of HVAC equipment, so programming is ONLY done at the factory, not in the field.

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Also asked, what is the difference between a PSC and ECM motor?

The big difference between the two models is that the PSC motor has one speed: full speed. Any time that the blower is on it blows at full force. The ECM model is a variable speed unit that will adjust the airflow to optimal levels based on the desired temperature of the home.

One may also ask, how does a variable speed ECM motor work? A variable-speed furnace includes a type of blower motor called an electronically commutated motor (ECM). These are DC motors that contain a magnet rotor and built-in inverter that cause them to run more efficiently than AC motors. When your traditional furnace runs, the fan motor blows at a constant speed.

Also to know is, how much does an ECM motor cost?

HVAC Blower Parts Cost

Belt $5-$100
Pulley $50-$250
Housing $100-$300
Capacitor $150-$450
ECM Motor Module $230-$830

Are ECM motors reliable?

Not only are they simple and inexpensive, but they've proven to be an extremely reliable component. The average lifespan of a PSC motor is around 40,000 hours, though an ECM surpasses it at 90,000 hours.

35 Related Question Answers Found

Does my furnace have an ECM motor?

Electronically commutated motors (ECM) represent an advance in blower motor efficiency that saves substantial energy and improves aspects of overall system performance. Variable speeds – Unlike an on/off PSC motor, a furnace ECM motor can operate at a range of outputs between zero and 100 percent.

How are ECM motors controlled?

ECM stands for an “electronically commutated motor” which basically means a motor that uses electronic controls to vary its speed. There are three types of ECM motors: constant cfm, constant rpm, and constant torque. It holds the logic that controls the motor.

What are the principal advantages of ECM motors?

What are the principal advantages of ECM motors? High efficiency, Low maintenance, Speed control, Constant CFM etc.

Do ECM motors use capacitors?

ECM Motors = Energy savings and added functionality
PSC motors, or permanent split capacitor, use non-polarized capacitors and brushes to deliver electricity to the rotating parts. These brushes are known to wear out over time. ECM motors do not use brushes, thereby reducing maintenance and extending service life.

Are ECM motors variable speed?


The term "Variable Speed" actually refers to the blower motor inside the furnace or air handler. It's an Electronically commutated motor, or (ECM). ECM's are DC motors that function using a built-in inverter and a magnet rotor, and as a result are able to achieve greater efficiency than most AC motors.

How does a ECM electric motor work?

ECMs are a type of DC motor. They are also called DC fan motors, EEM fan motors, and variable speed fan motors. The microprocessor uses a closed-loop feedback mechanism to more precisely control the magnetic fields, minimizing the eddy currents and losses used by traditional mechanically commutated motors.

How do I know if my AC blower motor is bad?

Symptoms of a Bad or Failing Heater Blower Motor
  1. Weak airflow from the vents. One of the first symptoms of a potential problem with the vehicle's heater blower motor is low airflow from the vents.
  2. Fan only blows at certain speeds. Another symptom of a bad or failing heater blower motor is a motor that only functions at certain speeds.
  3. No air from the vents.

How much is a blower motor?

The average cost for a blower motor replacement is between $363 and $394. Labor costs are estimated between $87 and $111 while parts are priced between $276 and $283. Estimate does not include taxes and fees.

Where is the blower located in the AC unit?

The blower fan is located inside a horizontal air conditioning unit in many home air conditioning systems, especially when the air handler is located in an attic or crawl area.

How much is an AC fan motor?


When your air conditioner's fan motor breaks, it will typically cost about $300 to $600 to replace. It's imperative to get this fixed quickly, since without a working fan motor your air conditioner's compressor can be the next domino to tumble. Its repair is even more significant — usually running closer to $2,000.

How long do blower motors last?

The moving parts in a furnace are generally limited to the blower fan and motor, while electronic valves and safety switches account for other components that may be affected by wear and tear. All these, however, are replaceable over the normal average 15-year span of a furnace's usual service life.

How much is a blower motor resistor?

The average cost for a blower motor resistor replacement is between $119 and $161. Labor costs are estimated between $47 and $60 while parts are priced between $72 and $101. Estimate does not include taxes and fees.

Why are ECM motors more efficient?

Because the motor operates at a constant speed, the use of energy is a constant and efficiency is lost. ECM or electronically commutated motors save energy and improve the efficient movement of air through your unit. ECM motors allow for variable speeds which can correspond to the unit's call for air flow.

What size blower motor do I need?

Rule of thumb is the blower should produce 440 CFM (cubic feet per minute) of air per ton. On a two ton system that is 880 cfm. This usually calculates out to about a 1/4 to 1/3 HP blower motor.

What does ECM stand for in motors?


Electronically Commutated Motor

What is a constant torque ECM motor?

Constant torque motors are high-efficiency, brushless DC motors that are based on the same ECM technology described in ECM 2.3 variable-speed motors. In other words, if the ESP changes, then the motor program will maintain the amount of torque for which it was programmed (this is not the same as constant airflow).

Is a variable speed blower worth it?

meaning they are not very energy efficient. Variable-speed furnace motor — A variable speed blower motor runs at different speeds to precisely control the flow of heated air throughout your home. If you don't have a 90% efficiency or higher furnace in your home, then yes it may well be worth the cost to upgrade.