6 Furnace Sounds You Shouldn’t Ignore

Furnaces are designed to operate quietly, so any unusual sounds could indicate a problem with your unit. Understanding these noises can help you determine whether it’s a minor issue or something that needs immediate attention from a qualified professional.

In this blog post, the heating experts at Michael Bonsby HVAC, Plumbing & Electrical discuss six sounds that you should never ignore from your furnace. If your furnace is making one of these noises, it may be time to contact our team online to book professional furnace repairs in Maryland, DC, or Virginia.

1. Why Your Furnace Is Rattling

One common noise for a furnace to make is rattling, which may indicate loose panels or screws, a broken or dislodged motor, or a cracked or damaged heat exchanger (which is a serious safety issue). To troubleshoot this issue, first check if the access panel is securely fastened. If it is and the issue persists, it’s best to schedule a professional inspection to prevent further damage.

2. Your Furnace Is Making a Squealing or Whistling Sound

When your furnace starts to squeal or whistle, there may be several culprits to blame, including:

• Worn-out or loose blower belts
• Airflow restrictions due to dirty filters
• Blower motor bearings in need of lubrication

Stopping this sound can be as simple as changing the air filter if it’s clogged. However, if the root cause of the problem lies within the belt or motor bearings, it’s best to trust a skilled HVAC technician by booking heating repair services.

3. The System Is Making Loud Booms, Knocking, or Rumbling Noises

Gas buildup in the furnace before ignition, dirty burners causing delayed ignition, and expanding and contracting ductwork can all cause your furnace to make loud booming, knocking, or rumbling noises.

If you hear loud booms, turn off the system and contact a professional immediately, as this could stem from a gas-related issue. Regular furnace maintenance is the best way to prevent dirty burners from causing disruptive ignition delays.

4. The Furnace Is Popping or Clicking

When you turn your furnace off or on, it’s normal for you to hear a popping or clicking noise. In some cases, however, this noise could point to a potential problem, such as a faulty or failing flame sensor or electrical issues within the furnace. If the clicking is persistent or the furnace fails to start, contact a technician to inspect the ignition system or flame sensor for issues.

5. Metal-on-Metal Sounds – Clanking or Scraping

Loud clanking or scraping noises are never a good sign and can point to several underlying problems, such as:

• Loose or broken blower wheels hitting other components
• Motor mount failures causing the fan to shift
• Foreign objects stuck in the blower

If you hear metal-on-metal noises, shut down your furnace immediately, as prolonged scraping can cause severe damage. A professional HVAC technician can realign or replace any damaged parts to restore proper functionality.

6. If Your Furnace Is Chirping, Here’s What You Need to Know

Chirping often occurs in your furnace when metal parts warm up at the start of the season. However, if the sound persists throughout the winter, it may be indicative of loose fan belts, pulley issues, or bearings needing lubrication. If the chirping sound continues even after the furnace has run for a while, book a furnace tune-up to prevent further wear and tear.

Schedule Furnace Repair in Maryland, DC, or VA Today!

At Michael Bonsby, our team understands that furnace noises are no joke, which is why we offer 24/7 emergency heating repair throughout the DMV area. With over 20 years of expertise in diagnosing and repairing furnace problems, you can count on us to deliver the fast, effective solution you need to restore total comfort quickly and efficiently.

We strive to provide complete transparency every step of the way, providing upfront pricing and no hidden fees so you always know your repair costs before work begins. With preventive maintenance plans available, we help keep your furnace running smoothly year-round.

Don’t ignore strange furnace noises — contact us online to book professional furnace repairs in Maryland, DC, or Virginia!