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 unit starts making weird noises. Some noises — like a couple of minor pops or clicks before the warm air beginning to blow — are perfectly harmless. But others could ruin the equipment or even jeopardize your health if you dismiss them. Of all the furnace noises you might encounter, here are nine that warrant an immediate furnace repair.

Scraping Furnace Noise

If you hear a sound like metal scraping on metal, this could suggest the blower wheel has loosened 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 urgent repair.

Loud Boom at Startup

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

A small boom each time your furnace turns on could crack the heat exchanger, an expensive repair that may necessitate you to replace the entire furnace. Don’t let it come to this! 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 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 unnecessary wear and tear. Our recommendation is to have this issue remedied right away to prevent premature furnace failure.

Chirping Noise

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

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

Screeching Furnace

Screeching noises are clear and certain signs that the fan belt is wearing out. If the fraying belt cracks, it could create all kinds of issues inside the furnace, damaging other components and contributing to 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 rapid series of clicks when they flip on and off. This is completely normal. That said, if the noise carries on longer than approximately 60 seconds, this could signal an electrical issue. To avoid risking a house fire, call a furnace repair professional to solve the problem promptly.

Thwapping Sounds

The blower motor should run properly when the furnace switches on. If you discover a thwapping sound that rapidly picks up speed as the blower gets going, this is a strong indication that something is stuck in the fan, and the blades are striking it with each rotation. A simple repair should be all it takes to stop this pestering 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 simple as a loose door cover, so start there. If the rattling remains, the most probable reason is a malfunctioning blower motor. Consider this 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 have them fixed quickly, you’ll pay less on your heating and cooling bills over the long haul.

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 if you want to be 100% sure, the easiest thing to do is to call a professional. At Service Experts Heating & Air Conditioning, we provide emergency furnace repair to get your unit performing properly as quickly as possible. Be confident 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 set things right! For additional information or to arrange a furnace repair visit, please speak a Service Experts office near you.