Motors 101: Learn About Common HVAC Motors and More

As an HVAC technician, you likely know that motors are a very important component of your customers’ heating and cooling systems. Choosing the right motor for the job is crucial. When replacing a motor in an HVAC system, there are a few questions you’ll want to ask yourself. What is the right motor for this particular application? Is the customer’s equipment still under warranty? How easy will it be for me to find the proper motor for the job?

In this article, we’ll talk about the roles motors play in cooling and heating systems, and give you a general overview of the different types of motors you may encounter on the job. And, we’ll explain when it’s the right time to use an OEM motor, and when to choose an aftermarket motor. Finally, we’ll share some tools with you that will help you find the right motor for any job. Keep reading to learn more!

The Importance of Motors in Cooling Systems

Air conditioning systems need the help of motors to operate properly. The system’s fan motor helps to ensure that the fan is properly drawing air in and out of the home. The fan serves to move hot air to the outside of the structure, and to move cool air throughout the duct system and into the rooms in the home. These motors can be repaired or replaced if necessary.

Air conditioner compressors also use motors, but since they are typically sealed inside the compressor housing, it can be difficult to determine if they’ve failed. This makes them difficult – and expensive – to replace.

The Importance of Heating System Motors

Much like a fan motor in an AC unit helps to move air inside and outside the home, heating system motors help move heated air throughout the home. Once the furnace heats the air, the blower motor pushes the heated air through the duct system and into the rooms of the home. Most often, heating systems use either a single speed or a variable speed motor. Because they are much more efficient, variable speed motors are becoming the standard in heating equipment.

Five Types of HVAC Motors

1. Compressor Motors
As we mentioned above, compressor motors are often the most difficult, and most expensive, motors to replace. This is because they are generally sealed inside either a semi-hermetic or hermetic compressor. Compressor motors are actually two motors in one – the run motor and the start motor. Because of the costly nature of replacing a compressor motor, you should generally try to determine if the compressor failure is definitely due to the motor, or if there is another issue with the compressor at play.

2. Inducer Motor
This type of motor is found in a gas furnace, and it usually doesn’t have to be replaced very often. The inducer motor’s job is to help the inducer blower draw air through the furnace’s combustion passage, allowing thorough heat transfer. Generally speaking, if you do come across a combustion fan (inducer) motor that needs to be replaced, it usually can be done fairly quickly and painlessly.

3. ECM Motors
ECM, or electronically commutated motors, are also commonly known as variable speed motors. These types of motors help to lower the amount of energy consumed by a furnace or air conditioner, and help ensure proper airflow throughout the HVAC system. With an ECM motor, the system will not simply operate on an “all or nothing” basis. It will be able to run at lower speeds, using less power at times – which can help your customers save on energy costs.

It is important to note that in some brands of equipment, the Department of Energy (DOE) mandated a minimum fan efficiency for residential furnaces that went into effect in July of 2019. Part of this mandate included the use of ECM motors in furnace equipment. As a result, most of the newer residential equipment will have ECM motors, so it’s important to have a good working knowledge of them.

4. Blower Motors
The blower motor serves an important function in the HVAC system. In a central heating system, it helps to move the heated air through vents and into the rooms of the home. If there is a central air conditioning system in the home, this same blower motor helps to move cool air throughout the home during the summer months. It is a critical component of the HVAC system, as it helps to maintain a comfortable temperature all throughout the home. Blower motors are generally available in single-speed or variable-speed configurations.

5. Condenser Fan Motors
Condenser fan motors take a lot of abuse. Because they function in the outdoor unit component of an air conditioning system, they’re exposed to rain, snow, sleet, and organics. They’re made to withstand all of this; however, it is more likely because of their exposure to the elements that they may need to be replaced on occasion.

OEM Motors vs. Aftermarket Motors

Regardless of the type of motor, all motors are either OEM or aftermarket. An OEM motor, also known as a factory authorized motor, is built to the exact specifications of a particular equipment manufacturer. The OEM motor must be built to the same standards as those of the individual manufacturer, using the same parts and components as are used in the factory that originally manufactured the cooling or heating equipment.

Aftermarket motors, which are also called universal motors, are made to work with a variety of different brands. While they are not built to the exact specifications of any particular manufacturer, this doesn’t mean they’re of poor quality or incompatible. It simply means that equipment manufacturers do not recognize them as a factory authorized part. It is, however, important to note that aftermarket motors range in quality, so it’s important to choose a reputable distributor.

Of course, you might be wondering when to use an OEM motor versus when to use an aftermarket motor. Generally speaking, you should use an OEM motor whenever you need to replace a motor in a specific brand of equipment that is still under warranty. Why? Because failure to do so will likely void the manufacturer warranty. And, that will lead to an unhappy customer. Not to mention, choosing an OEM motor can be easier on you as the contractor, because most of these motors are made to be an exact, drop-in replacement on equipment. While they may be costlier, it’s still a good idea to choose an OEM motor when you need to make a replacement on a newer system.

Quality aftermarket motors are a good choice when you need to make a repair on equipment that is no longer under warranty. They are generally readily available, and many contractors choose to stock a variety of universal motors so that they can be prepared for virtually any job. It can be difficult to find OEM motors for older or obsolete equipment, so in these cases an aftermarket motor can help get the job done without requiring a more expensive equipment replacement.

Finding the right motor is easy when you choose a reputable distributor.

It’s very important to choose a reputable distributor when you purchase replacement parts of any sort, including motors. This is because otherwise, you might get poor quality parts that can damage your customer’s equipment and cause safety concerns. When looking for a distributor, ask the following questions:

  • Is the distributor associated with reputable equipment brands, such as Carrier®?
  • Does the distributor carry a wide variety of motor types, so that you can find the right motor for any application?
  • Can they supply you with both OEM motors and high-quality universal motors?
  • Does the distributor have a tool or database that can help you find the right motor for the job?
  • Do they provide the accessories needed for motor replacement as well?

Your Carrier/Bryant® Distribution Center checks all of the boxes above and more. We’re dedicated to helping you find the perfect motor, no matter what the job requirements. You’ll be able to choose from Factory Authorized Motors, which are exact, drop-in replacements for Carrier, Bryant, and Payne® equipment, as well as a robust offering of universal motors that can help with virtually any application. When you need a motor for your customer’s equipment, make sure to stop by one of our distributorships first. We’ll help you find the motors and accessories you need, and get back to the job in no time. 


Mike Brown, Product Manager