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 might be caught off guard if the equipment starts making strange noises. Some noises — like several faint pops or clicks ahead of the warm air beginning to blow — are normal and harmless. But others could affect the equipment or even endanger your health if you neglect 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 against metal, this could mean the blower wheel has come loose from the motor shaft, or the wheel or motor mount has broken. Regardless of the specific problem, you should switch off your furnace if you notice a scraping sound and call a professional for an emergency 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 likely 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, an expensive repair that may force you to remove and replace the entire furnace. Act before it gets to this point! 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 high-pitched squealing furnace noise usually signifies poor lubrication. Like many mechanical equipment with moving parts inside, they need lightweight oil to run smoothly. If these parts are dry, components rub against each other and cause unnecessary wear and tear. We suggest getting this situation remedied right away to protect against premature furnace failure.

Chirping Noise

The sound of a bird trapped in your furnace definitely warrants investigation. If you notice chirping during the first furnace cycle of the season, it could merely mean your furnace is warming up after months of no use. In this case, the sound should dissipate after a few cycles.

However, if the chirping doesn’t subside, it could indicate the pulley for the blower motor is misaligned or the mounting plate is touching the blower wheel. This isn’t always a safety risk, but the only choice to get rid of the annoying furnace noise is to have a technician conduct a repair.

Screeching Furnace

Screeching noises are an unmistakable warning sign that the fan belt is failing. If the fraying belt cracks, it could create all kinds of issues inside the furnace, damaging other components and resulting in a much more expensive repair. Avoid this hassle and cost by changing the worn-out belt sooner rather than later.

Continual Clicking.

Some furnaces give off a fast series of clicks when they flip on and off. There is nothing unusual about that. That said, if the noise lasts longer than a minute or so, this could suggest an electrical complication. 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 function smoothly when the furnace activates. If you hear a thwapping sound that rapidly picks up speed as the blower gets going, this likely means something is stuck in the fan, and the blades are hitting it with each rotation. A quick repair should be all that's required to stop this annoying 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 plausible root cause is a declining blower motor. Consider this a warning sign to have your furnace repaired before it entirely fails.

Whistling or Vibrating

Noises such as a teapot whistle or the hum of a vibrating item are signals of a problem with the air intake vent. If the whistling or vibrating comes from a vent, your ductwork is likely detached, allowing conditioned air to release. These aren’t critical 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 match these descriptions? It might be nothing, 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 have emergency furnace repair to get your system functioning properly as fast 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 get in touch with a Service Experts office near you.

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