How to quiet a noisy furnace: Top DIY tips for a peaceful home

There’s nothing quite like the comfort of a warm home when the weather outside is chilly. But if your furnace starts making strange clunking or screeching sounds, it can quickly disrupt that cozy feeling. Understanding the cause of these noises can help you address the issue early and keep your furnace running smoothly. This guide covers common furnace noise problems and provides step-by-step instructions on how to fix them yourself.

The information here may not perfectly match your specific furnace model. We aim to provide helpful advice for a variety of DIY fixes, but different models can have their unique features. For the most accurate guidance, it’s a good idea to consult your furnace manual or reach out to us if you have any questions.

High-pitched squealing or whistling sounds

If your furnace is making a high-pitched squeal or a whistling sound, it’s often related to airflow problems. This type of noise is pretty common, but luckily, it’s usually an easy fix. What it might be:

• Blower motor speed issues: If the blower speed is set too high or low, it can make the motor strain, causing that squealing sound.
• Dirty or clogged air filters: A clogged air filter reduces airflow, which can make the blower motor work harder and create noise.
• Dust buildup in ducts: If there’s a lot of dust or debris in your ducts, it can mess with the airflow, resulting in a whistling or squealing sound.

How to fix it:

Adjust blower speed settings

1. Turn off the furnace and unplug it.
2. Look for the blower motor (usually behind a panel).
3. Check your furnace’s wiring diagram to adjust the blower speed as recommended by the manufacturer.
4. If you’re not sure, try adjusting the motor speed slightly to see if it alleviates the squealing.

Replace or clean the air filter

1. Find the air filter slot, typically near the return air duct.
2. Remove the old filter and check it for dirt or damage.
3. Clean the filter if it’s reusable, or replace it with a new one if needed.
4. Make sure the arrows on the new filter point toward the furnace for proper airflow.

Clear out the ducts

1. Turn off the furnace.
2. Remove vent covers and use a vacuum hose with a brush attachment to clean out dust and debris.
3. Wipe down the vent covers before replacing them.

Once you’ve done these steps, turn the furnace back on and listen to see if the squealing or whistling stops. If the noise continues, we can check the next section for further troubleshooting.

Rattling or banging sounds

If your furnace is making rattling or banging sounds, it can be a sign that something is loose or out of place. These sounds can be pretty loud and disruptive, but the good news is they’re often caused by something simple that you can fix yourself. What it might be:

• Loose panels or covers: If any access panels or furnace covers are loose, they can vibrate and rattle as the furnace operates.
• Worn motor mounts: The motor mounts hold the blower motor in place. Over time, they can wear out or become loose, causing the motor to wobble and create a banging sound.
• Blower wheel issues: If the blower wheel is damaged, off-balance, or obstructed, it can make a loud banging noise as it spins.

How to fix it:

Tighten or secure loose panels

1. Power down the furnace.
2. Check all the access panels and doors.
3. Use a screwdriver to tighten any screws or latches that may be loose.
4. Ensure all covers are securely fastened before turning the furnace back on.

Check motor mounts

1. Open the furnace cabinet and locate the blower motor.
2. Inspect the motor mounts for any wear or looseness.
3. Tighten any loose bolts or screws. If the mounts are in bad shape, replace them with new ones.

Inspect the blower wheel

1. Carefully remove the blower assembly (consult your furnace manual for specific instructions).
2. Look at the blower wheel for any cracks, bends, or debris.
3. If it’s damaged, clean it off or replace the blower wheel.

Read more: 12 things you should know about portable space heaters

Constant humming or buzzing

A constant hum or buzz from your furnace might indicate an issue with the electrical components, which is typically an easy fix. This sound could be coming from the wiring, transformer, or blower motor. What it might be:

• Loose wires: If any electrical connections are loose, it can cause a humming or buzzing noise.
• Faulty transformer: If your furnace’s transformer is failing or overloaded, it could produce a buzzing sound.
• Blower motor issues: An old or worn-out blower motor can start humming or buzzing as it struggles to run.

How to fix it:

Check the wiring

1. First, turn off the power to the furnace at the breaker.
2. Open the control panel and inspect the wires for any loose connections, frayed insulation, or signs of damage.
3. Tighten any loose wires using a screwdriver or replace any damaged wires.

Inspect the transformer

1. Locate the transformer in your furnace (refer to your manual for its exact location).
2. When the furnace is on, listen to see if the buzzing sound is coming from the transformer.
3. If it is, the transformer may need to be replaced. Disconnect the old transformer and connect the new one, making sure the wiring is secure.

Look over the blower motor

1. Turn off the power to the furnace.
2. Inspect the blower motor for any visible wear or damage.
3. If the motor has lubrication points, add a few drops of oil to keep it running smoothly.
4. If the motor is still humming after lubrication, it may need to be replaced. Use a multimeter to check the motor’s resistance and compare it to the specifications in your furnace’s manual.

Read more: Your guide to choosing a space heater

Keeping things running smoothly

A clean furnace is a happy furnace. Regular maintenance can ward off many noise issues.

1. Change filters often: Swap out or clean filters every month or so when you’re using the furnace a lot.
2. Clean the ducts: Consider getting your ducts cleaned yearly to remove gunk buildup.
3. Keep the area around the furnace tidy: Dust and debris can affect efficiency, so keep things clean.

Use the right parts

When replacing anything, make sure you’re using parts that fit your furnace model.

Need help finding the right stuff? Check out our guide on how to find your furnace’s model number.

Read more: 12 simple space heater safety tips for this winter

Stay in the loop with more tips

Keep your home cozy and your appliances happy by following us for more DIY guides and tricks. Join our community on Facebook and Twitter to stay in the know.

For parts, advice, and expert help, swing by AppliancePartsPros.com. We’re here for you every step of the way.