Is Your Furnace Making Odd Noises?

If your furnace (heater) starts making loud or unusual noises, it might be a clear sign of trouble. Furnaces are often the one thing in your home that can be neglected. However, you likely recognize what sounds are expected from your furnace when it’s running as it should, so the noise that’s out of the ordinary needs your attention. Your furnace may get your attention by making one or two of these sounds.

  • Screeching Noise: If you hear a screeching noise, it could be something wrong with the motor, or a bearing inside the motor that is producing 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. Sometimes you are sometimes able to wiggle the wheel to get the alignment to resolve itself, but if you don’t know what you’re doing, it’s simply a better idea to have an expert HVAC tech handle things.
  • Rattling sound: If you hear a noisy rattling sound when your furnace shuts off, it is probably the metal parts to your furnace cooling down. However, it can also be something more unpleasant. The blower can be out of alignment or an error 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 most often in the pipes, instead of the furnace itself. This can happen when the pipes are able to cool down and contract after the furnace turns off.
  • Loud Boom or Thud: A loud boom or thud sound may have come from the ducts. They occasionally expand and contract in cold weather, namely if the furnace’s surroundings aren’t heated. However, it may also be evidence that the burners in the furnace are dirty and need to be cleaned. These are comparatively easy to clean on your own using hot soapy water. If you want to clean these yourself, be sure they are completely dry before putting them back. If you learn that it’s not the ducts or the burners, it may be that your gas valve is defective (should you have a gas furnace), which can cause a delayed ignition. In the majority of cases, it is better to call Precision so one of our experienced HVAC technicians can diagnose the problem.
  • Pinging and or Popping: A pinging or popping sound is usually coming from one of the ducts and is not often something to worry about.
  • Odd Vibrating Noise or Whining: If you hear an odd vibrating noise or whining, it may reveal 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 stop 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 may be a motor bearing going out.
  • Crackling Noise: A crackling noise is more than likely coming from the metal parts of your furnace cooling down when the furnace shuts off.
  • Clunking and Banging: A clunking and banging sound is often a cracked belt. If you hear this noise you should have a Precision HVAC tech out to your home to replace the belt.


For the most part, if your furnace is making sounds that are out of the ordinary its certainly a good idea to schedule one of our NATE certified HVAC technicians to visit your home to do a system diagnosis to reveal any potential problems before it’s too late. As they say, an ounce of prevention is worth a pound of cure.