Is Your Furnace Making Odd Noises?

If your furnace (heater) is making loud or unusual noises, it could be a clear sign of trouble. Furnaces tend to be the one system in your home that can be left alone. However, you probably understand what sounds are expected from your furnace when it’s operating normally, so noise that’s 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 might be a problem with the motor, or a bearing inside the motor that is making the noise.
  • Metallic Chirping Noise: If you hear a metallic chirping noise, it could be caused by the wheel being out of alignment, a motor mount might be coming loose, or your bearings could be worn down. On occasion you may be able to adjust the wheel to get the alignment back to normal, but if you aren’t certain of what you’re doing, it’s usually a better idea to have an expert HVAC tech take a look.
  • Rattling sound: If you hear a noisy rattling sound when your furnace turns off, it is usually the metal parts to your furnace cooling down. However, it can also be something more severe. The blower could 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 more than likely in the pipes, instead of the furnace itself. This may 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 start somewhere inside the ducts. They sometimes expand and contract in cold weather, particularly if the furnace’s surroundings aren’t heated. However, it might also be a sign that the burners in the furnace are dirty and need to be cleaned. These are pretty easy to clean yourself with hot soapy water. If you want to clean these yourself, make sure they are completely dry before putting them back. If you learn that it’s not the ducts or the burners, it might be that your gas valve is malfunctioning (assuming you have a gas furnace), which can cause a delayed ignition. In many cases, it is wise to call Precision so one of our knowledgeable 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 really something to worry about.
  • Odd Vibrating Noise or Whining: If you hear a strange vibrating noise or whining, it may point to a problem with your furnace. It might 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 prevent this noise by turning the “off/pilot/on” control to reduce the burner flame.
  • Rattling Noise When the Furnace Starts Up: If you hear a rattling noise when the furnace activates, it could 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 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 come to your home to replace the belt.


For the most part, 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 stop by 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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