9 Common Furnace Noises and What They Mean

If you've had your furnace for several winter seasons, you know how it’s supposed to sound. So you might be caught off guard if the equipment starts making unfamiliar noises. Some noises — like a couple of minor pops or clicks prior to the warm air beginning to blow — are perfectly harmless. But others could ruin the equipment or even threaten your health if you neglect them. Among the possible noises that you may hear, here are nine that are worthy of an immediate furnace repair.

Scraping Furnace Noise

When you hear a sound like metal against metal, this could suggest the blower wheel is becoming detached from the motor shaft, or the wheel or motor mount is broke. Regardless of the specific problem, you should turn off your furnace if you discover a scraping sound and call a professional for an critical repair.

Loud Boom at Startup

When you fire up your furnace, the burners should ignite immediately and get started heating your home. A loud boom at startup probably means the burners are dirty, which causes a delayed ignition. When the gas eventually does ignite, you hear this terrifying furnace noise.

A small blast each time your furnace turns on could crack the heat exchanger, an expensive repair that may necessitate you to switch out the entire furnace. Don’t let it come to this! Shut 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 generally implies poor lubrication. Multiple parts of a furnace need lightweight oil to operate smoothly. If the parts are not lubricated, components rub against each other and cause unnecessary 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 hear chirping coming from the furnace upon the first activation of the season, it could simply mean your furnace is warming up after several months of no use. In this case, the sound should end after a few cycles.

However, if the chirping does not end, it could indicate the pulley for the blower motor is crooked or the mounting plate is coming in contact with the blower wheel. This isn’t automatically a safety hazard, but the only option to eliminate 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 splits, it could create all kinds of issues inside the furnace, breaking other components and leading to 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 quick series of clicks when they turn on and off. This is completely normal. That said, if the noise carries on longer than about one minute, this could indicate an electrical issue. To avoid risking a house fire, call a furnace repair professional to correct the problem promptly.

Thwapping Sounds

The blower motor should operate smoothly when the furnace switches on. If you notice a thwapping sound that dramatically picks up speed as the blower gets going, this could mean something is stuck in the fan, and the blades are smacking it with each rotation. A simple repair should be all that's required to eliminate this annoying furnace noise and reduce the risk of 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 verify that option first. If the rattling persists, the most plausible culprit is a failing blower motor. Treat this as a warning sign to have your furnace repaired before it entirely fails.

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 leak. These aren’t emergency matters, but if you address it promptly, 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 unsure 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 provide emergency furnace repair to get your system functioning properly as soon 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 additional information or to arrange a furnace repair visit, please speak a Service Experts office near you.