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Don’t Ignore These End-of-Season Furnace Noises


It’s the end of the heating season, and you’re probably just about ready to shut your furnace down in favor of your cooling system, right? Before you do that though, it’s important to make sure you address any heating repair needs you might have, so that you don’t find yourself with an inefficient or even completely broken down furnace next fall when you need the system again.

One of the most apparent signs that something is amiss with your furnace is loud, unfamiliar noises. Now, your furnace is always going to make some noise. You’re probably even used to the standard sounds you hear from it… like the whir of the motor starting up for the blower fan or the whoosh of the air coming through the vents.

However, you know the typical noises you hear on a daily basis better than anyone. So if your furnace starts making unfamiliar or loud noises, it’s time to give our team a call for repairs. Read on as we uncover some of the most common signs we get called for and what they might mean.

Loud Banging When System Starts Up

We’ll start with the sound that probably alarms you the most—hearing a loud banging noise from your furnace can be very concerning. If this is happening on a consistent basis (not just at startup) then it could have to do with the air ducts or sheet metal siding of the furnace expanding and contracting—the result of poor duct installation or improper furnace sizing.

If this noise is only occurring when the furnace starts up, however, then there is definitely cause for concern. This can be due to something like a dirty furnace burner. What happens is the dirt layer enables gas to buildup, and a sort of “mini-explosion” happens when the burners ignite.

While this might not have an immediate impact on your furnace or home comfort, it eventually can leak to cracked heat exchangers and subsequent carbon monoxide exposure, which can be quite dangerous.

Squealing Sounds

Any squealing noise you hear coming from the furnace might be from a lack of lubrication, or a blower fan belt that has worn out. This means it’s an easy fix for our technicians, but it’s still a big deal! This is because if you let the problem go on for too long, the fan can actually stop working, stopping the furnace from operating when you need it most.

This is definitely one of those problems that is best to fix now rather than waiting to discover a broken down furnace.

Low Rumble

If you hear a low rumbling sound, it’s likely loudest when you’re right next to the unit. It’s hard to say what the cause is without seeing or hearing the furnace on our own. One common culprit though, is a pilot flame that’s too low.

Check your flame to ensure that it’s blue instead of yellow or orange—and call us if it’s the latter.

Otherwise, a rumbling sound could be coming from a carbon monoxide leak. The best thing you can do if you hear this sound is turn off your system and call us for an emergency inspection and potential repairs.

For professional furnace repair in Skokie, IL, contact Shavitz Heating and Air Conditioning.

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