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 unit starts making unfamiliar noises. Some noises — like a couple of faint pops or clicks before the warm air beginning to blow — are completely harmless. But others could damage the equipment or even endanger your health if you dismiss them. While there are many more furnace noises to consider, here are nine that warrant an immediate furnace repair.

Scraping Furnace Noise

If you hear a sound like metal against metal, this could indicate the blower wheel has come loose from the motor shaft, or the wheel or motor mount is broke. No matter the specific problem, you should turn off your furnace if you discover 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 quickly and get started 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 boom each time your furnace turns on could bust the heat exchanger, a costly repair that might require you to remove and replace the entire furnace. Don’t let it come to this! 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 high-pitched squealing furnace noise typically indicates poor lubrication. Shaft bearings and other moving parts require lightweight oil to run smoothly. If the parts are not lubricated, components grate against each other and cause needless wear and tear. Look into having this issue remedied right away to avoid premature furnace failure.

Chirping Noise

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

However, if the chirping continues, it could mean the pulley for the blower motor is out of alignment or the mounting plate is coming in contact with the blower wheel. This isn’t always a safety threat, but the only solution to get rid of the irritating furnace noise is to have a technician conduct a repair.

Screeching Furnace

Screeching noises are an unmistakable warning sign that the fan belt is wearing out. If the fraying belt splits, it could spin inside the furnace, harming other components and resulting in a much more expensive repair. Avoid this hassle and cost by replacing the worn-out belt sooner rather than later.

Repeated Clicking.

Some furnaces give off a fast series of clicks when they turn on and off. This is common and no reason to be concerned. However, if the noise continues longer than a minute or so, this could indicate an electrical issue. Don't risk an electrical fire! Simply call a furnace repair professional to correct the problem without delay.

Thwapping Sounds

The blower motor should operate properly when the furnace switches on. If you notice a thwapping sound that quickly picks up speed as the blower gets going, this could mean something is stuck in the fan, and the blades are striking it with each rotation. A simple repair should be all you need to eliminate this annoying furnace noise and protect against damaging the blower motor.

Rattling Furnace

A few different problems can cause your furnace to rattle. It might be as simple as a loose door cover, so check this first. If the rattling persists, the most plausible reason is a declining blower motor. Treat this as 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 detached, allowing conditioned air to leak. These aren’t emergency matters, but if you fix it soon, you’ll pay less on your heating and cooling bills in the long run.

Schedule Furnace Repair with Service Experts Heating & Air Conditioning

Are you undecided whether the furnace noises you hear correspond to these descriptions? It might be nothing, 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 heater functioning properly as soon as possible. Rest assured 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 fix it! For more information or to arrange a furnace repair visit, please contact a Service Experts office near you.

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