What Causes A Furnace Blower Motor To Go Bad? (Find Out Now!)

Eli Smith
by Eli Smith

With the winter months coming fast, ensuring that your furnace motor stays in good condition is paramount. Because of this, it is good to be aware of what causes a furnace blower motor to go bad. Having this knowledge will prepare you for quick action should a repair be required.

A blower motor can go bad if the motor is dirty, and you need to clean it with a brush to fix it. You can also add standard motor oil to the motor if it is low to lubricate it and help it blow. Install or repair vents to prevent condensation that can cause a blower motor to go bad.

Another common issue that causes your furnace to go bad comes from moisture. Moisture comes from leaks from other appliances. It is more common to have these leaks occur during colder seasons, as defrosting causes condensation.

Below, we will give you signs to find out that your furnace blower motor is failing. We will also go through various fixes you can follow to solve the problem.

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What Is A Blower Motor?

A blower motor is a part of your HVAC heating system, which pushes heated air throughout your house. It does this through a spinning fan, which pushes air through the vents of your home. A blower motor typically comes in two forms: direct drive and belt drive.

Direct drive blower motors are a type of motor connected directly to the furnace’s fan. These are the most common types of furnace motors you find in residential homes. Belt drive blower motors are connected to a pulley used to turn the fan. As a result, they have a bit more power, making them less common in residential applications.

To determine what type you have, look to see if your furnace is more extensive or has any pulley systems. If you have a commercial-style motor, it will require an extra bit of care. Given that these are uncommon, we will be focusing on direct drive blower motors.

Signs That Your Furnace Blower Motor Is Going Bad

There are a few signs to keep an eye out for when your motor is going bad. Below are a few potential issues you could run into:

Unusual Sounds

Typically, the noise you hear coming from your furnace is no more than a low hum. If you hear anything in addition to that, it can be a sign of trouble to come. Unusual sounds come with age, so this can be a sign of you needing to make a replacement.


Most furnace systems are designed to last up to twenty years. After that twenty years, it is only natural for the wear to catch up in your furnace. HVAC technology has improved leaps and bounds since the early 2000s. Even if you don’t have furnace issues, upgrading can reduce the cost of heating in your house.

Need For Frequent Repairs

A large number of short-term fixes may help your furnace get to the next month, but it won’t address long-term issues. If your furnace is requiring numerous small repairs, you might need a replacement. However, if these repairs are related to overheating or moisture, solving what is causing those issues may fix your problem.

Starting And Stopping Repeatedly

If your furnace stops after a few minutes of running, it is another sign of your furnace blower motor going bad. It is also a sign that your engine is overheating. This can cause significant long-term effects if left untreated.

Abnormally High Energy Bills

A heater that works overtime will cause the energy bills in your house to spike. It is a sign that some parts may be wearing out and therefore need replacement.

The Fan Only Blows At Certain Speeds

Your furnace will typically have multiple speed settings. If it only functions at certain speeds, it is a sign that your blower motor can no longer handle higher rates.

Issues like this could also come from settings in the control panel, so try a hard reboot to fix it first. A hard reboot can be done by flipping the circuit breaker, wait thirty seconds, and turning it back on. After waiting, try the higher fan setting again. If it still doesn’t work, your motor may be going out.

Furnace Blower Motor Overheating And Ways You Can Fix It

The most common furnace issue you run into is overheating. Overheating can also be accompanied by a burning smell, which is a sign that your furnace may be on the verge of giving out. Below are a few options you have for fixing this issue.

Clean Your Motor

The most common cause of overheating is not cleaning your motor. Below are some quick steps you can follow to fix this problem.

  • Turn off power and gas to the furnace
  • Clean surfaces with a lightly damp rag
  • Unscrew control panel
  • Remove and clean the blower with using a small brush
  • Dust off the pilot light and the igniter
  • Clean the flame sensor with a fine cloth
  • Replace the air filter

People typically combine this with other activities, like checking the drive belt if running a belt drive motor. Otherwise, be sure that everything is secure and clear of dust before re-igniting the burners.

Lubricate Your Motor

With age, the oil on your motor can begin to fade. As a result, it is a good idea to lubricate your engine every so often. Because you aren’t dealing with an automobile, standard motor oil is unsuitable for this task. Deciding to ignore this will result in your motor being damaged.

Also, WD40 does not function as long-term motor oil. Please do not use it to lubricate your heater. When lubricating a motor, the oil needs to go into each port. Look for caps around the blower motor. Many times, you can find these caps with support from your owner’s manual.

Given that this process requires a bit of technical know-how, you can also contact a professional. If done correctly, most HVAC systems need to be lubricated annually.

Check Your Motor’s Voltage

Overheating may also be caused by running your furnace at a voltage outside of the recommended value. While this isn’t common, the typical solution is to contact the HVAC technician who installed it. If running a home generator or being located in a rural area, this may require an electrician’s work. If you smell something burning, turn off your furnace using the breaker.

How To Prevent Your Furnace Blower Motor From Having Excess Moisture

While not quite as standard, a furnace blower motor can also fail due to excess moisture. You see this problem often with built-up condensation, which is caused by the following issues:

Improper Ducting

IF the built-up heat stays inside the location with the heater, it can increase humidity. This higher humidity can drip back onto the blower motor, causing electric shorts.

Eventually, this will result in your blower mower going out altogether. Cleaning out your ducts may solve this issue. Otherwise, you may see about hiring a professional that can install your vents so that they may not cause condensation.

Appliance Using Water Installed Above Heater

Heaters are usually in the basement, giving them ample opportunity to install unwanted things above them. These things include humidifiers, dishwashers, and washing machines.

When ducting is nearby these water-based appliances, the condensation built up in them can cause major electronic issues. Sometimes, you can solve this issue through more insulation. Otherwise, you may have to contact a company to adjust the ducts.

Freezing And Unfreezing Of Your Condensate Drain Line

Many HVAC systems have condensate drain lines that remove excess moisture from your furnace. If the line is not functioning, water can prevent your system from starting. This issue is more common for those who have a combination of AC and Heater.

All systems have to have a way for condensation to escape. If your furnace is the cause of leaking water, we have a detailed guide on solving this problem.

How Can You Prevent Your Furnace Blower Motor From Going Bad?

The best way of preventing your furnace blower motor from giving up is to have a regular checkup schedule. Follow these tips below:

Regularly Replace Your Filter

The air filter prevents your furnace from building up any large, dirty particles. As a result, your system can stay clean and burn clean, improving your air quality.

Depending on how often you use your furnace, you only have to change it once a year. But colder climates will have you seeing this air filter change every six months. If you do not change your air filter, it will cause overheating.

Have Your Furnace Inspected By A Trusted HVAC Technician

Have a trusted HVAC individual come to your house every one or two years to check your furnace’s condition. A good technician will tell you of any areas of concern before they are allowed to become real problems.

Be sure that you trust this technician, as some HVAC providers have a habit of quoting you unrealistic numbers to try and make a quick buck. Be sure that you check out the reviews of any specialist you hire.

Listen To Your Furnace

Every so often, it is a good idea to listen to your furnace. Unusual noises can be the sign of your blower motor going out. In some cases, noises can be a sign of something dangerous. By listening to your furnace, you may save yourself from a far more expensive repair.

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Related Questions

What is the average lifespan of a furnace blower motor?

With proper maintenance, a blower motor can last up to twenty years. This is the industry standard and they’re designed to last many years with very little special attention required. Though, that does not mean that a furnace blower motor will not fail.How long the motor lasts ultimately depends on use and age. So, even if the manufacturer states that their blower motor will last you two decades, you should expect a lifespan of between 20 and 20 years due to use, age, and proactive maintenance. However, with little to no maintenance, you can see these blower motors going out in as little as five years.

How much does it cost to replace a furnace blower motor?

The average nationwide cost to replace a furnace blower motor is between $400 and $600, including parts and labor. A single-speed blower motor replacement will run you about $450, while a variable-speed motor costs $600, or more.Although the speed of the motor is an important cost factor, the cost of repair also depends on the where your furnace is located in your home, what your warranty covers, and local labor rates.

Should I repair my furnace blower motor or replace my entire furnace?

The cost to replace an entire furnace is generally between $2,000 and $6,000. This is considerably more expensive than what it would cost to repair your furnace blower motor. Though, there are some instances where it’s necessary. If you have a limited budget or you plan to sell your home in a couple years, keeping up with frequent repairs to extend the life of your furnace may make the most sense.Otherwise, if your furnace is more than 10 to 15 years old and requires some pricey repairs, you should consider replacing it instead of paying out of pocket for parts and labor. After all, a new furnace means you enjoy the benefits of brand-new parts, upgraded features, and an updated manufacturer’s warranty. Not to mention, you might also experience a drop in your utility bills due to enhance efficiency.

Eli Smith
Eli Smith

I'm a guy who becomes the expert of whatever I stumble upon, writing-wise. I've written tons about cool home products, home improvement, and smart technology in the home. I'm also the proud father of a kiddo born on new years, making my holidays very busy.

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