How To Quiet A Noisy Furnace Blower (Do This!)

Upgraded Home Team
by Upgraded Home Team

Adding some warmth to your home through the winter can keep your space cozy and comfortable. Many people opt for a furnace blower to help push the hot air through the house effectively. While this is a great solution to heat a home, sometimes the furnace blower can become quite loud. Fixing a furnace blower yourself is possible for the technical and savvy DIY homeowner.

A noisy furnace blower can be caused by several problems, including a faulty blower motor, dirty air filters, or undersized or leaky air ducts. Oiling the motor and replacing parts combined with some routine maintenance for the air filters should help reduce the amount of noise your furnace blower makes.

While fixing a motor and cleaning filters is within the realm of work a homeowner can do, often work with the air ducts should be left to a professional technician. Sometimes, simply adding additional return vents, sealing leaks in the ducts, or adding the right-sized vents can help eliminate unwanted furnace blower noise.

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What If My Furnace Makes a Screeching or Rattling Noise?

If you hear a screeching or rattling noise when you turn on your furnace blower, you may have an issue with the motor that powers the blower. The blower is responsible for moving warm air throughout your house, and the motor helps propel the fans that pull the warm air. Over time, the motor can become dry and damaged through repeated use.

A savvy homeowner may be able to repair a blower motor themselves. To perform some routine maintenance and diagnostic testing, you should:

Step 1: Power Off

Turn the power off to the furnace and locate the furnace blower motor. Locate and take note of the furnace blower location, as well as where each wire is. You may want to take a picture with your mobile phone to note the wire location.

Step 2: Removal

Carefully disconnect the wires from the blower motor and remove the blower motor from the unit. You will want to have enough room to work with the motor outside of the furnace.

Step 3: Disassembly

Very carefully, disassemble the motor. You will want to add oil to lubricate the rubber components and belts. If any components are dry rotted or worn, replace them with new parts.

Step 4: Reassembly

Once the motor is inspected, oiled, and worn components replaced, reassemble the motor. Rewire the motor into place, taking special care to ensure all the wires are reconnected in the correct position. Restore power, and turn the furnace on to ensure the motor runs properly.

If you feel uncomfortable disconnecting and working with a motor, leave this job to the professionals. A professional HVAC technician will be able to come and disassemble and repair your furnace blower motor if you are unsure. Not only will an HVAC technician have the right tools and experience to work on your motor, but they will have the right equipment and replacement parts to get your motor in good working condition again.

What If My Blower Makes a Squealing Noise?

Usually, if you hear a squealing noise come from your furnace blower motor, one of the belts is worn. A worn belt can be caused by dry rot or routine wear and tear. When the belt wears out, the dry rubber makes a loud noise as it moves through the gears within the furnace blower motor.

Fixing a dry belt can be accomplished with the furnace blower motor removed from the furnace. While the motor is apart, be sure to correctly oil, or even replace, the belt. Reassembling and running the belt newly oiled should fix the problem with a squealing furnace blower motor.

What Routine Maintenance Helps Reduce Furnace Blower Noise?

Sometimes your furnace may make a whistling sound or may have a louder hum than usual. Many of these noisy problems with your furnace blower can be fixed with some routine maintenance items. Some easy fixes to prevent furnace blower noise includes:

  • Change Dirty Filters – If you hear a whistling sound coming from your furnace blower, you may have an issue with dirty filters. When filters become too packed with dirt and dust, they can block the airflow from getting to your blower motor. This impacted filter can make the blower much louder than it should be. Commit to routine filter changes to prevent a noisy blower. It is a good practice to change your filter about once every three months. You may need to clean it more frequently if you have a dusty home or pets.
  • Fill Gaps – Sometimes, the issue with a noisy blower isn’t the motor for the blower at all, but the air ducts that receive the blown air. Do a visual inspection of your air ducts and determine if you can see any light coming through the sides of the ducts. If you have gaps in your ducts, it can force the air out of the gap, making a whistling sound. Air duct gaps can be easily patched with duct tape or foil tape. Inspecting your air ducts is good routine maintenance to make sure your ducts are in good working condition.
  • Dust – Furnaces are often in basements that don’t get too much routine cleaning. To keep your furnace and blower in good working condition, be sure to keep the area dust-free. If dust is allowed to collect on the furnace blower, it can cause fans and components to wear unevenly. A build-up of dust on the fan blades or motor can cause the motor to make loud noises when it runs.

What Long-Term Adjustments Can I Make?

While routine maintenance and some quick repairs to the furnace blower may solve your noise issue, other repairs are more in-depth but will last for years. Some options you may have to quiet your furnace blower long term include:

  • Return Air Ducts – If your furnace blower makes a whistling noise, there may be a pressure imbalance in your home. This imbalance happens when there is a pressure difference between the intake and output parts of your vents. You can determine if this is the problem causing your noise if you open the filter door on your furnace and notice the sound reduces. To fix this problem, you can add more return air ducts throughout your home. This fix is a significant modification to your existing home and will require the help of a professional.
  • Add Sound Insulation – Sometimes, a furnace blower will be inherently noisy. Adding some insulation to the system can help dampen the sound. Most commonly, technicians will recommend using a melamine foam around the blower intake. Secure the foam with metal wire to make sure the foam doesn’t get sucked into the blower.
  • Add Bolts – It helps to add modifications to the furnace blower motor itself to keep it quiet. Adding rubber mounts to the feet of the motor can help absorb some of the rattle and sound. You can also fasten the motor to the furnace itself using bolts to create a secure connection that reduces vibration and potential noise. A professional technician can make these modifications to your motor and make sure the right-sized rubber feet are purchased for the motor.
  • Resize Air Ducts – Sometimes, furnace blower noise is caused by air ducts that are incorrectly sized for your home. The furnace blower works to blow hot air through your house, pushing the warm air through the air ducts. If your air ducts are too small, they can create a loud whistling noise. While replacing all the air ducts in your home is a big job for a professional to take on, it can help solve various issues, including furnace blower noise. Resizing the air ducts for your home will make your home quieter and allow your HVAC system to run more efficiently.

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Related Questions

How do I know when my furnace needs replaced?

Sometimes, constant noise and rattles are too much for simple repairs, and a complete furnace replacement is necessary. You may need to replace your furnace if you notice higher than usual utility bills that can’t otherwise be explained with usage. Further, you may be paying for frequent repairs for your furnace as age becomes an issue.Your furnace will become less effective over time, running longer to maintain temperature. Or, you may notice your furnace is getting rusty, worn, or old.

Is hearing a loud boom from the furnace normal?

When you first turn your furnace blower on, it is not uncommon to hear a loud boom sound coming from your ductwork. Most ductwork is metal, which can expand and contract, especially when the temperature changes. When the hot air is initially pushed through the metal air ducts, the ducts will expand, causing a loud booming or popping sound.This sound is entirely normal with the changing temperature and is usually heard right when the furnace turns on. Ongoing or repeated booming sounds, even when the furnace has been running for some time, should be inspected by a furnace technician.

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Upgraded Home Team
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