Are There Strange Noises Coming From Your Furnace? What Do They Mean?

During fall and winter, your furnace should provide consistent heat smoothly, efficiently, and quietly. It shouldn’t sound like there’s a party going on inside.

Ignoring strange furnace sounds because “it’s just always done that” or “it eventually goes away” is unwise. In fact, it can be downright dangerous.

In some instances, what’s causing the noise can damage your furnace beyond anything furnace repair is capable of fixing.

  Contact us at Dows ClimateCare ASAP If your furnace makes any of these noises:

Furnace repair


A metal-on-metal scraping or grinding noise usually means something’s going on with the blower wheel and should be dealt with immediately.

Just as its name implies, the blower wheel’s job is to blow air out of the furnace and throughout your home. The wheel itself is connected to a motor shaft via a set screw.

That loud, abrasive sound could be happening because:

  • The wheel has fallen off the shaft: The wheel’s now free to bounce and bang against the blower casing. If this is taken care of quickly, all that’s required is a furnace maintenance
  • The wheel itself is broken: Replacing the wheel is the only option in this case.
  • The mount is broken: If the mount is broken, the entire blower assembly unit – wheel, screw, and mount – has fallen and damaged the housing. This problem is quite serious.

Furnace burners

Noise is just one furnace concern to be mindful of.
Learn what the others are in your FREE copy of The Top 3 Homeowner Concerns about Furnaces (and How to Overcome Them).

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Those banging and popping sounds are caused by one of two things:

  • Air ducts expanding and contracting: As the blower turns off and on, the metal ducts expand and contract. This usually means your air ducts are undersized.
  • Dirty burners: If something’s preventing the burners from igniting immediately, a small amount of gas builds up. That bang/pop is actually the gas igniting.

TIP: Over time those little gas explosions can end up cracking the heat exchanger, which is quite costly to fix. So it’s best to put a stop to them ASAP.


A squealing or whining sound is more annoying than dangerous. Still, it needs to be addressed sooner rather than later.

More often than not, this awful grating noise is caused by:

  • Blower belts: Loose or slipped belts need to be put back in place while frayed belts need to be replaced.
  • Dry shaft bearings: Adding oil to the ports should do the trick.
  • Blower motor malfunction: If it’s not too bad, a repair is enough. If the damage is more severe, it’ll need to be replaced outright.

Hear any strange sounds coming from your furnace? Call us now

Whatever you do, don’t open up your furnace to try to locate and solve the problem yourself. Behind the casing is a complex piece of machinery that’s full of electricity and gas.

You might make the issue worse. Or you could end up injuring yourself.

The safest way to quiet a noisy furnace is to contact us and tell us what you hear. We’ll get back to you to learn more and make a plan to get out and see you ASAP.