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 it will likely catch your attention if the equipment starts making odd sounds. Some noises — like a couple of small pops or clicks before 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 are worthy of an immediate furnace repair.

Scraping Furnace Noise

The moment you hear a sound like metal rubbing on metal, this could indicate the blower wheel has come loose from the motor shaft, or the wheel or motor mount is damaged or failing. No matter what the precise problem, you should turn off your furnace if you hear a scraping sound and call a professional for an urgent repair.

Loud Boom at Startup

When you fire up your furnace, the burners should ignite immediately 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 shocking furnace noise.

A small boom each time your furnace turns on could bust the heat exchanger, a pricey repair that may force you to replace the entire furnace. Don't wait to act when you hear a noise like that! Switch off your furnace if you hear a loud boom at startup, and do not activate it again until it has been repaired.

Squealing or Whining Sounds

A high-pitched squealing furnace noise typically signifies poor lubrication. Shaft bearings and other moving parts require lightweight oil to operate smoothly. Without this, components rub against each other and cause needless wear and tear. Look into having this situation remedied right away to prevent premature furnace failure.

Chirping Noise

The sound of a bird lodged 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 simply mean your furnace is warming up after an extended period of no use. In this case, the sound should end after a few cycles.

However, if the chirping doesn’t subside, it could imply the pulley for the blower motor is misaligned or the mounting plate is coming in contact with the blower wheel. This isn’t always a safety risk, but the only solution to eliminate the irritating furnace noise is to have a technician conduct a repair.

Screeching Furnace

Screeching noises are clear and certain signs that the fan belt is failing. If the fraying belt breaks, it could create all kinds of issues inside the furnace, damaging other components and leading to a much more expensive repair. Insulate yourself from this hassle by replacing the worn-out belt sooner rather than later.

Constant Clicking.

Some furnaces give off a rapid series of clicks when they flip on and off. There is nothing unusual about that. However, if the noise lasts longer than approximately 60 seconds, this could indicate an electrical complication. Don't risk an electrical fire! Simply call a furnace repair professional to correct the problem promptly.

Thwapping Sounds

The blower motor should perform without problems 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 quick repair should be all that's required to stop this bothersome furnace noise and reduce the risk of damaging the blower motor.

Rattling Furnace

A few different problems can cause your furnace to rattle. It might be as basic as a loose door cover, so start there. If the rattling remains, the most plausible root cause is a failing blower motor. Take this as a warning sign to have your furnace repaired before it is an urgent situation.

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 escape. These aren’t emergency matters, but if you fix it soon, you’ll spend less on your heating and cooling bills long term.

Schedule Furnace Repair with Service Experts Heating & Air Conditioning

Are you undecided whether the furnace noises you hear correspond to 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 provide emergency furnace repair to get your system performing properly as quickly as possible. Rest assured 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! To find out more or to arrange a furnace repair visit, please contact a Service Experts office near you.

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