Is Your Furnace Making Odd Noises?


If your furnace (heater) begins making loud or bizarre noises, it might be a useful sign of trouble. Furnaces are usually the one thing in your home that can be ignored. However, you also know what sounds are expected from your furnace when it’s operating like it’s supposed to, so something out of the ordinary needs your attention. Your furnace could get your attention by making one or two of these sounds.

  • Screeching Noise: If you hear a screeching noise, it could be an issue with the motor, or a bearing in the motor that is making the noise.
  • Metallic Chirping Noise: If you hear a metallic chirping noise, it might be caused by the wheel being out of alignment, a motor mount might be broken or loose, or your bearings could be worn down. Occasionally you might be able to adjust the wheel to get the alignment corrected, but if you are unsure about what you’re doing, it’s usually a better idea to have an experienced HVAC tech check things out.
  • Rattling sound: If you hear a noisy rattling sound when your furnace turns off, it is likely the metal parts to your furnace cooling down. However, it might also be something more severe. The blower might be out of alignment or a problem in the motor occurred. If you hear this noise you should give Precision a call.
  • Clanging noise: If you hear a clanging noise, the problem is typically in the pipes, rather than the furnace itself. This tends to happen when the pipes are able to cool down and contract after the furnace switches off.
  • Loud Boom or Thud: A loud boom or thud sound may be caused by the ducts. They occasionally expand and contract in cold weather, most often if the furnace’s surroundings aren’t heated. However, it might also be an indication that the burners in the furnace are dirty and need to be cleaned. These are comparatively easy to clean yourself with hot soapy water. If you do attempt to clean these yourself, don’t forget to check that they are totally dry before placing them back inside. If you find out that it’s not the ducts or the burners, it could be that your gas valve is faulty (assuming you have a gas furnace), which can result in a delayed ignition. In many cases, it is a good idea to call Precision so one of our expert HVAC technicians can resolve the problem.
  • Pinging and or Popping: A pinging or popping sound is typically coming from one of the ducts and is not often something to fret over.
  • Odd Vibrating Noise or Whining: If you hear an unusual vibrating noise or whining, it may be coming from a problem with your furnace. It can be serious, so a Precision technician really needs to check it out.
  • Loud Humming: A loud humming noise may come from when the furnace burners light and its cold outside. You can eliminate this noise by turning the “off/pilot/on” control to shrink the burner flame.
  • Rattling Noise When the Furnace Starts Up: If you hear a rattling noise when the furnace starts up, it might be a motor bearing going out.
  • Crackling Noise: A crackling noise is more than likely caused by the metal parts of your furnace cooling down when the furnace turns off.
  • Clunking and Banging: A clunking and banging sound is often a cracked belt. If you hear this noise you ought to have a Precision HVAC tech out to your home to replace the belt.


If you want to be on the safe side, if your furnace is making sounds that are seem out of place its definitely a good idea to schedule one of our NATE Certified HVAC technicians to visit your home to do a system diagnosis to uncover any surprise problems before it’s too late. As they say, an ounce of prevention is worth a pound of cure.

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