Common Furnace Noises That You Should Never Neglect

Furnance All furnaces make some noises when running, but as furnaces age, they tend to make more noises that are often a symptom of a needed repair or indications that your furnace may need to be replaced soon by an External link opens in new tab or windowHVAC company in Cartersville, GA. No matter how old your furnace is, it’s important to pay attention to a few of these common sounds so that you can get the necessary repairs as soon as possible. Here are some sounds to listen for and what they might mean.


Loud Pop or Bang

A loud pop or bang is usually the result of dirty burners. Dirty burners make it difficult for ignition to occur, so gas will start to build up, and when it finally ignites, it will make a loud banging or popping sound. This sound is definitely cause for concern when dirty burners are to blame because it can either cause a small explosion or it may crack the heat exchanger, which can be an expensive repair. Another potential cause of this sound is from the air ducts expanding or contracting. Some minor popping is normal because the ducts expand and contract when the furnace turns on and off; however, loud banging from the ducts may indicate more serious problems with your ductwork.


Rattling sounds can be from loose screws on the front panel, so you can often listen to see where the rattling is coming from. Rattling sounds can also indicate loose ductwork that needs to have screws tightened or tape applied to resecure the duct connections.

HVAC repair service Squealing or Whining

Squealing or whining sounds usually mean a part has come loose or that’s it worn out and damaged. A common culprit is a loose or frayed blower belt or a blower motor that’s malfunctioning. Sometimes the furnace will make a squealing sound if the shaft bearings need lubrication. In any case, if your furnace is making this sound, you need to call for HVAC repair right away because ignoring any of these repairs can cause additional damage to your furnace. The repairs are difficult to do on your own without the specific tools and training professional HVAC technicians have.

Scraping Metal

Your furnace should never sound like metal is scraping on metal. If you hear this sound, turn off the system right away and call for help. In most cases, metal scraping sounds are due to a broken blower fan or wheel that has come loose and is hitting the blower housing. If this happens, the fan or wheel may need to be tightened or otherwise repaired, or it may need to be replaced altogether.

Loud Humming

The furnace will make some humming noises when it runs, but if it seems unusually loud there could be cause for concern. Some furnaces just have a louder transformer, especially older furnaces. But when the humming is excessively loud, you might have a bad fan or capacitor that needs to be replaced.

Repeated Clicking

Sometimes when you turn on the furnace it may click a few times repeatedly. This is often a simple problem due to a faulty thermostat. Fortunately, thermostats are a common component of HVAC systems, so technicians will be able to easily determine if the thermostat needs to be replaced or if the wiring to the furnace is to blame.

If you’ve noticed any unusual sounds when your furnace runs, be sure to contact Shriver Mechanical, Inc. right away, for repair to your External link opens in new tab or windowHVAC in Cartersville, GA.