9 Common Furnace Noises and What They Mean

Over time, when you fire up your furnace, you know how it’s supposed to sound. So you'll likely notice if the equipment starts making strange sounds. Some noises — like a couple of small pops or clicks before the warm air beginning to blow — are normal and harmless. But others could ruin the equipment or even endanger your health if you dismiss them. Of all the furnace noises you might encounter, here are nine that warrant an immediate furnace repair.

Scraping Furnace Noise

The moment you hear a sound like metal against metal, this could suggest the blower wheel has loosened from the motor shaft, or the wheel or motor mount is damaged or failing. No matter the precise problem, you should shut off your furnace if you discover a scraping sound and call a professional for an emergency repair.

Loud Boom at Startup

When your furnace starts up, the burners should ignite right away and start heating your home. A loud boom at startup likely means the burners are dirty, producing a delayed ignition. When the gas finally does ignite, you hear this terrifying furnace noise.

A small blast each time your furnace turns on could bust the heat exchanger, a costly repair that may necessitate 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 avoid using it again until it has been repaired.

Squealing or Whining Sounds

A squealing furnace noise typically indicates poor lubrication. Multiple parts of a furnace need lightweight oil to operate smoothly. If these parts are dry, components grind against each other and cause unwanted wear and tear. We suggest getting this issue remedied right away to prevent premature furnace failure.

Chirping Noise

The sound of a bird caught 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 several months of no use. In this situation, the sound should go away after a few cycles.

However, if the chirping doesn’t subside, it could indicate the pulley for the blower motor is out of alignment or the mounting plate is contacting the blower wheel. This isn’t necessarily a safety risk, but the only choice to get rid of 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 splits, it could whip around inside the furnace, breaking other components and resulting in a much more expensive repair. Insulate yourself from this hassle by changing the worn-out belt sooner rather than later.

Repeated Clicking.

Some furnaces give off a fast series of clicks when they switch on and off. There is nothing unusual about that. That said, if the noise lasts longer than about one minute, this could suggest an electrical issue. Don't risk an electrical fire! Simply call a furnace repair professional to solve the problem without delay.

Thwapping Sounds

The blower motor should perform properly when the furnace switches on. If you hear a thwapping sound that dramatically picks up speed as the blower gets going, this likely means something is caught in the fan, and the blades are smacking it with each rotation. A straightforward 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 easy as a loose door cover, so verify that option first. If the rattling continues, the most likely reason is a declining blower motor. Take this as a warning sign to have your furnace repaired before it breaks down completely.

Whistling or Vibrating

When your furnace has an air intake vent issue, you will often hear a whistling or humming vibration sound. If the whistling or vibrating comes from a vent, your ductwork is likely loose, allowing conditioned air to leak. These aren’t urgent matters, but if you address it promptly, you’ll save money on your heating and cooling bills over the long haul.

Schedule Furnace Repair with Service Experts Heating & Air Conditioning

Are you uncertain whether the furnace noises you hear match these descriptions? Perhaps nothing is wrong, but the only way to know for sure is to call a professional. At Service Experts Heating & Air Conditioning, we offer emergency furnace repair to get your system back up and running as quickly as possible. Be confident knowing that we stand behind our work with a one-year, 100% satisfaction guarantee. If you’re unhappy 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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