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Mike Smith Heating & Air Conditioning, LLC Blog

These Furnace Sounds Could Spell Disaster


We often talk on this blog about the importance of having repairs done promptly when any part of your HVAC system is experiencing problems. Delaying repairs can cause small problems to worsen, put strain on other parts of the system, or even cause damage to unrelated components. 

The trick is knowing how to catch problems early, and one of the best ways to do that is listening to the sounds your furnace makes. Pay attention to the sounds you hear when all is going well. They should be steady and consistent, and not very loud. Once you’re familiar with the good sounds, you’re more likely to notice right away when strange sounds occur. What strange sounds might you hear when your furnace is having trouble, and what kind of trouble do they indicate? Read on to find out.


Does your furnace sound like a dramatic robot who is simply exhausted with life and wearing down? If you hear a groaning sound, it’s not actually likely that your furnace is having an existential crisis. It’s far more probable that the motor bearings have worn down, and you need furnace service in Sterlington, LA. Noticing the sound and scheduling repairs promptly means replacing the bearings. Ignoring the problem and delaying repair could mean having to replace the whole motor. 


Does your furnace sound like it has terrible indigestion, or like a small thunderstorm is brewing inside it? A dirty burner can cause your furnace to make a worrisome rumbling noise. Repairs should be easy, and this issue can be avoided in the future by making sure you schedule furnace maintenance every year.

Clanking or Squealing

Many (but not all) furnaces have a motor that is separate from the fan. The two are connected with a belt that transfers the motion of the motor to the fan. Clanking or squealing can indicate a problem with the belt. It may be coming loose, or it may have cracked and started to tear. In this case, prompt repair means replacing the belt. Failure to repair it promptly can result in the belt flying out of position at high velocity and damaging other components inside your furnace.


Loud, frequent clicking is the sound you should take most seriously. If you hear this, shut down your furnace and call for emergency repairs. If you’re lucky, it’s just a loose screw allowing a panel to click against the body of the furnace cabinet. But it can also be the first indication of a cracked heat exchanger. Since this is the component that keeps combustion gasses separate from the air you breathe in your home, a crack in the heat exchanger can lead to carbon monoxide poisoning. 

We’re always happy to hear from customers wondering whether a suspicious furnace noise is a cause for alarm. It’s better to be safe than sorry, and sometimes a bit of information can go a long way toward easing your mind. 

Contact Mike Smith Heating & Air Conditioning, LLC. We provide “Professional grade service.”

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