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 you'll likely notice if the system starts making strange noises. Some noises — like a couple of small pops or clicks ahead of the warm air beginning to blow — are completely harmless. But others could damage the equipment or even jeopardize 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 rubbing on metal, this could suggest the blower wheel has come loose from the motor shaft, or the wheel or motor mount is broke. No matter what the exact problem, you should switch off your furnace if you discover a scraping sound and call a professional for an urgent repair.

Loud Boom at Startup

When you start your furnace, the burners should ignite quickly and start heating your home. A loud boom at startup likely means the burners are dirty, producing a delayed ignition. When the gas at last does ignite, you hear this frightening furnace noise.

A small explosion each time your furnace turns on could bust the heat exchanger, an expensive 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 don’t use it again until it has been repaired.

Squealing or Whining Sounds

A screaky or loud squealing furnace noise typically implies poor lubrication. Shaft bearings and other moving parts require lightweight oil to operate smoothly. Without this, components rub against each other and cause unwanted wear and tear. Our recommendation is to have this issue remedied right away to protect against premature furnace failure.

Chirping Noise

The sound of a bird entrapped in your furnace absolutely warrants investigation. If you notice chirping during the first furnace cycle of the season, it could simply 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 continues, it could mean the pulley for the blower motor is misaligned or the mounting plate is coming in contact with the blower wheel. This isn’t necessarily a safety hazard, but the only solution to stop the annoying furnace noise is to have a technician conduct a repair.

Screeching Furnace

Screeching noises are definite indicators that the fan belt is deteriorating. If the fraying belt breaks, 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 replacing the worn-out belt sooner rather than later.

Constant Clicking.

Some furnaces give off a rapid series of clicks when they turn on and off. There is nothing unusual about that. That said, if the noise carries on longer than about one minute, this could signal 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 properly when the furnace activates. If you discover a thwapping sound that quickly picks up speed as the blower gets going, this likely means something is snagged in the fan, and the blades are smacking it with each rotation. A simple repair should be all you need to get rid of 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 remains, the most probable reason 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

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 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 in the long run.

Schedule Furnace Repair with Service Experts Heating & Air Conditioning

Are you unsure whether the furnace noises you hear align with 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 have emergency furnace repair to get your heater functioning properly as soon as possible. Feel safe 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 fix it! For additional information or to arrange a furnace repair visit, please speak a Service Experts office near you.

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