A bad furnace blower motor usually causes weak airflow, strange noises (screaking or grinding), overheating, or completely failing to turn on. The quickest way to check if it's dead is to inspect if the fan wheel spins freely by hand or if it has seized.
How to Tell if a Furnace Blower Motor is Bad
Replacing a furnace blower motor typically costs between $400 and $1,800, with the national average landing around $600 to $800 for parts and labor. Your total bill will depend heavily on whether you have a standard single-speed motor or a high-efficiency variable-speed motor.
To reset a furnace blower motor, turn off power to the furnace using the emergency switch or the circuit breaker. Wait 2-3 minutes, then locate the red or yellow reset button typically found on the blower motor housing. Press it firmly, and restore power.
On average, a furnace blower motor lasts between 10 and 20 years. However, this lifespan can be significantly shortened by a lack of maintenance, specifically if air filters are not changed regularly, causing the motor to overheat and overwork.
If your furnace is under 10 years old and the rest of the system is working well, replacing the blower motor is usually the smarter move. But if your unit is over 15 years old or has frequent issues, a full replacement may be more cost-effective in the long run.
The heat exchanger is often considered the most costly part of a furnace to repair or replace. It is a critical component that transfers heat from the combustion process to the air that circulates throughout your home. Over time, heat exchangers can crack due to the constant heating and cooling cycles they undergo.
Your furnace’s reset button is typically a small, bright red or yellow button located either inside the blower compartment, near the burner assembly, or directly on the motor housing.
Diagnosing a faulty blower motor versus a bad resistor typically comes down to what fan speeds are working. If the fan only works on the highest setting, the resistor is usually the culprit. If the fan doesn't work on any speed, or if it makes strange noises, the motor itself is likely failing.
Most furnaces have a reset button near the blower compartment itself, though the exact location may vary depending on the make and model. It's usually red or yellow and small in size. Consult your furnace manual for guidance if you're unsure where it is.
Is it worth replacing a furnace blower motor? Yes, replacing a furnace blower motor can be worth it if the furnace is still in good condition. A new motor restores airflow, improves heating efficiency, and extends the lifespan of your system. It's generally more cost-effective than replacing the entire furnace.
Blower motor replacement typically takes 2 to 3 hours, depending on the system's complexity and accessibility. Simpler replacements, such as for standard systems, may take around 2 hours, while more complex systems, especially those with harder-to-reach motors, can take 3 hours or more.
Blower motors can overheat due to various issues such as dust buildup, a clogged air filter, or mechanical failure. If your HVAC system frequently shuts off or goes into “safe mode,” it might be because the blower motor is overheating.
The $5,000 rule is a guideline to help homeowners decide whether to repair or replace their HVAC system. You multiply the age of your unit by the cost of the needed repair. If that number exceeds $5,000, replacing your HVAC system is often more cost-effective.
Testing a blower motor involves checking for incoming power, testing the motor's internal resistance with a multimeter, or performing a direct power test. Common tools needed are a multimeter, alligator clips, and a 12V12 cap V12𝑉 or 120V120 cap V120𝑉 power source depending on your application.
Which one to replace? If high setting works and medium and low do not, replace the resistor. If blower motor is spinning but makes noise, replace the blower motor. If you hear noise and only high setting works, replace both.
The blower motor resistor can be removed after the bolts have been removed. The wire should be linked to the blower motor's positive terminal, and the negative terminal should be attached to the blower motor's negative terminal. This will turn off the resistor and allow the blower motor to run at full speed.
A bad furnace blower motor usually causes weak airflow, strange noises (screaking or grinding), overheating, or completely failing to turn on. The quickest way to check if it's dead is to inspect if the fan wheel spins freely by hand or if it has seized.
If it doesn't start at all, you can press the button one more time. But, if you press the reset button and your furnace goes on and turns off again, don't press the button again. Continuing to press the reset button can damage your system. Doing so will pump more oil into the furnace and worsen any existing issues.
To get your furnace to kick on, first verify your thermostat is set to "Heat" and raised at least 5 degrees above room temperature. Next, check that the furnace power switch (usually resembling a standard light switch on or near the unit) is toggled "ON".
What fails first on a furnace? The most common early failures are the furnace ignitor or flame sensor, as they experience regular wear and tear and are critical to starting the heating cycle.
Try the Salvation Army, a local church, or a community action agency. Their rules may be different. Ask About Payment Plans: Many local HVAC contractors, including Smart Climate Solutions, offer payment plans for urgent repairs because we believe everyone deserves a warm home.
A furnace typically lasts between 15 and 20 years. However, the exact lifespan varies based on the type of unit and how well it is maintained.