How Long Do Blower Motors Last?
Oddly, answering the question “How long do blower motors last?” is both one of the simplest and most difficult questions to answer for HVAC professionals. By design, the blower motor is never the weakest link among components, so it should last as long as the entire system it’s part of, whether that’s a heat pump, furnace, or forced-air cooling system. Unfortunately, the blower motor is also exposed to conditions that the rest of the system is not, and can have a drastically shortened lifespan as a result.
Average Lifespans for Different HVAC Systems
For quick reference, most HVAC systems are designed for a lifetime of up to 20 years. More specifically, systems that include blower motors have a lifespan of roughly:
- Air-Source Heat Pumps: 10 to 12 years, with a maximum of 15 years or more
- Furnaces: 10 to 20 years, depending on maintenance schedules
- DX Air Conditioners: 15 to 20 years, depending on maintenance schedules and manufacturer quality
When manufacturers rate individual components, they expect that all parts will last as long as the overall lifetime. So why do many technicians find that they need to replace blower motors?
Conditions That Affect How Long Blower Motors Last
Blower motors are often exposed to the harshest conditions facing an HVAC system because they receive outside air that is only treated or moderated by an air filter. This means that changes in humidity, corrosive elements, and other contaminants can all affect blower motor lifetime.
Even in an ideal situation, the blower motor is still at the mercy of outside factors: most are constructed as brushed electrical systems, and the brushes wear down over time. This process is exacerbated if the motor begins to overheat. This can happen when there is inadequate airflow through the system or if belts and other components are not operating properly.
Signs of Early Failure
Since components are interconnected, not every symptom is a sign that there is an early end to a blower motor. However, technicians who notice the following symptoms should consider checking the blower motor connections and electrical terminals:
- Little or No Airflow: If there is no air moving through the system, it starts with the blower motor. If there is not enough fresh air to run over the cooling coils or the furnace burners, then there will be no treated air to move within the system.
- Abnormal Sounds: Since blower motors are enclosed systems, often a change in sound is the first sign that something could become an issue. This can include anything from rattling, squealing of belt issues, or screeching as the motor tries to continue working even as a specific part is slowing it down.
- Smells or Early Shutdowns: If there is a significant impingement within the system, the motor will struggle to work against it. Smells are a good sign that something is burning up or grinding into an early failure. Similarly, blower motors that have the right controls will notice changes in function and shut them down early. If this is the case, you will notice rapid cycling of the entire system, since the entire process begins when the blower motor is turned on.
Choosing to Repair or Replace Blower Motors
As noted above, blower motors are enclosed components. The upside of this is that it helps maximize lifetimes by preventing the penetration of dust, corrosive materials, and the like. Unfortunately, it also means that they can be difficult to repair without installing a complete replacement.
Often, the first step for technicians should be understanding that a replacement is required and then looking for preventive steps to keep the new motor from facing similar stresses. Issues like increased dust, improper filter replacement, and other concerns can be passed along to the facility manager to ensure that the next service visit happens closer to the expected lifetime based on the manufacturer’s idea of how long blower motors last.
Find the Replacement Blower Motors You Need
As a leading distributor for the most trusted names in commercial HVAC and dehumidification, Affiliated Parts has the kits that you need in order to maximize the performance and efficiency of your systems or those of your clients. Shop our complete list of replacement HVAC blower motors or contact us for more information.