9 Common Furnace Noises and What They Mean

If you've had your furnace for several winter seasons, you know how it’s supposed to sound. So you might be caught off guard if the unit starts making unfamiliar sounds. Some noises — like a few faint pops or clicks prior to the warm air beginning to blow — are normal and harmless. But others could impair the equipment or even jeopardize your health if you dismiss them. Of all the furnace noises you might encounter, here are nine that justify an immediate furnace repair.

Scraping Furnace Noise

If you hear a sound like metal rubbing on metal, this could suggest the blower wheel is becoming detached from the motor shaft, or the wheel or motor mount is damaged or failing. No matter the precise problem, you should power down your furnace if you notice a scraping sound and call a professional for an emergency repair.

Loud Boom at Startup

When you start your furnace, the burners should ignite right away and begin heating your home. A loud boom at startup potentially means the burners are dirty, producing a delayed ignition. When the gas at last does ignite, you hear this shocking furnace noise.

A small boom each time your furnace turns on could crack the heat exchanger, a pricey repair that might require you to switch out the entire furnace. Don’t let it come to this! Switch off your furnace if you hear a loud boom at startup, and don’t use it again until it has been repaired.

Squealing or Whining Sounds

A high-pitched squealing furnace noise generally indicates poor lubrication. Shaft bearings and other moving parts require lightweight oil to run smoothly. If these parts are dry, components grate against each other and cause unwanted wear and tear. Our recommendation is to have this situation remedied right away to avoid premature furnace failure.

Chirping Noise

The sound of a bird trapped in your furnace absolutely warrants investigation. If you notice chirping when you fire up the furnace for the first time of the season, it could just mean your furnace is warming up after an extended period of no use. In cases like this, the sound should end after a few cycles.

However, if the chirping doesn’t subside, it could indicate the pulley for the blower motor is crooked or the mounting plate is touching the blower wheel. This isn’t automatically a safety threat, but the only choice to eliminate the pesky furnace noise is to have a technician perform a repair.

Screeching Furnace

Screeching noises are definite indicators that the fan belt is deteriorating. If the fraying belt cracks, it could create all kinds of issues inside the furnace, breaking other components and leading to a much more expensive repair. You can protect yourself from this unexpected expense by exchanging the worn-out belt sooner rather than later.

Constant Clicking.

Some furnaces give off a fast series of clicks when they flip on and off. This is common and no reason to be concerned. That said, if the noise continues longer than approximately 60 seconds, this could signal an electrical issue. Don't risk your home catching fire by a faulty electrical situation; call a furnace repair professional to solve the problem immediately.

Thwapping Sounds

The blower motor should run smoothly when the furnace switches on. If you discover a thwapping sound that dramatically picks up speed as the blower gets going, this likely means something is stuck in the fan, and the blades are striking it with each rotation. A quick repair should be all that's required to get rid of this annoying furnace noise and protect against damaging the blower motor.

Rattling Furnace

A rattling furnace can be caused by multiple issues. It might be as basic as a loose door cover, so check this first. If the rattling continues, the most likely root cause is a declining blower motor. Consider this a warning sign to have your furnace repaired before it breaks down completely.

Whistling or Vibrating

When these noises come from the furnace, it could mean the air intake vent is dislodged. If the whistling or vibrating comes from a vent, your ductwork is likely separated somewhere, allowing conditioned air to leak. These aren’t urgent matters, but if you address it promptly, you’ll spend less on your heating and cooling bills over the long haul.

Schedule Furnace Repair with Service Experts Heating & Air Conditioning

Are you undecided whether the furnace noises you hear correspond to these descriptions? Maybe nothing’s wrong, but for your peace of mind, the best thing to do is to call a professional. At Service Experts Heating & Air Conditioning, we offer emergency furnace repair to get your system performing properly as quickly as possible. Feel safe knowing that we stand behind our work with a one-year, 100% satisfaction guarantee. If you’re disappointed with our work anytime in the next 12 months, we’ll get it corrected! For more information or to arrange a furnace repair visit, please contact a Service Experts office near you.

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