9 Common Furnace Noises and What They Mean

After a few years of running your furnace every winter, you know how it’s supposed to sound. So it will likely catch your attention if the system starts making weird sounds. Some noises — like several small pops or clicks ahead of the warm air beginning to blow — are completely harmless. But others could affect the equipment or even endanger your health if you ignore 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 scraping on metal, this could indicate the blower wheel has loosened from the motor shaft, or the wheel or motor mount is damaged or failing. Regardless of the exact problem, you should turn off your furnace if you hear 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 potentially means the burners are dirty, resulting in delayed ignition. When the gas eventually does ignite, you hear this terrifying furnace noise.

A small blast each time your furnace turns on could break the heat exchanger, an expensive repair that might require you to replace the entire furnace. Don't wait to act when you hear a noise like that! Turn 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 generally indicates poor lubrication. Multiple parts of a furnace need lightweight oil to function smoothly. Without this, components rub against each other and cause unnecessary wear and tear. We suggest getting this situation remedied right away to avoid premature furnace failure.

Chirping Noise

The sound of a bird caught in your furnace certainly warrants investigation. If you notice chirping during the first furnace cycle of the season, it could simply mean your furnace is warming up after several months of no use. In this situation, the sound should end after a few cycles.

However, if the chirping continues, it could indicate the pulley for the blower motor is misaligned or the mounting plate is contacting the blower wheel. This isn’t necessarily a safety hazard, but the only option to eliminate the annoying furnace noise is to have a technician conduct a repair.

Screeching Furnace

Screeching noises are definite indicators that the fan belt is failing. If the fraying belt breaks, it could whip around inside the furnace, harming other components and contributing to a much more expensive repair. You can protect yourself from this unexpected expense by changing the worn-out belt sooner rather than later.

Persistent Clicking.

Some furnaces give off a quick series of clicks when they turn on and off. This is common and no reason to be concerned. Having said that, if the noise continues longer than approximately 60 seconds, this could signal an electrical problem. To avoid risking a house fire, call a furnace repair professional to fix the problem promptly.

Thwapping Sounds

The blower motor should perform properly when the furnace switches on. If you hear a thwapping sound that rapidly picks up speed as the blower gets going, this is a strong indication that something is snagged 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 bothersome furnace noise and protect against damaging the blower motor.

Rattling Furnace

There are several possible reasons for your furnace to produce a rattling sound. It might be as easy as a loose door cover, so check this first. If the rattling remains, the most probable reason is a declining blower motor. Consider this a warning sign to have your furnace repaired before it entirely fails.

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 separated somewhere, allowing conditioned air to escape. These aren’t urgent matters, but if you have them fixed quickly, you’ll spend less on your heating and cooling bills long term.

Schedule Furnace Repair with Service Experts Heating & Air Conditioning

Are you uncertain whether the furnace noises you hear correspond to these descriptions? Maybe nothing’s wrong, but if you want to be 100% sure, the easiest 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 fast as possible. Be confident knowing that we stand behind our work with a one-year, 100% satisfaction guarantee. If you’re dissatisfied with our work anytime in the next 12 months, we’ll set things right! To find out more or to arrange a furnace repair visit, please contact a Service Experts office near you.

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