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Is Your Furnace Making These Ominous Noises?

woman-covering-her-earsWith Halloween quickly approaching, and an eerie feeling in the air, it’d be easy to pretend the strange noises you’re hearing from around your home are silly trick-or-treaters outside or even a haunted house—but that’s probably not the source of these noises.

Do the noises coincide with your furnace running? We hate to break it to you, but if that’s the case, then those ominous noises are very likely coming from your heating system.

Strange and unfamiliar noises are often the first sign a failing or struggling furnace gives off. Read on for some of the most common.


Inside your furnace system, there is a component called the air handler, which is responsible for circulating air throughout your living space while the system is on. The air handler motor uses a number of oiled bearings to keep friction as low as possible.

These bearings do a great job of keeping that friction low, but they do eventually wear out as a natural part of wear and tear. The more worn-out these bearings get, the more friction your furnace’s air handler accumulates, eventually causing your system to make a grinding noise whenever the furnace is operating. The bearings will eventually need to be replaced before they fail altogether, otherwise, the air handler motor can overheat and burn out.

Rapid Cycles

Does it sound like your furnace is turning on for only a short time, rapidly shutting off, only to quickly start up again? This is called short-cycling, which can be caused by a number of things that result in heat becoming trapped within the system—due to either an electrical problem, a clogged air filter, or a malfunctioning air handler.

Short-cycling prevents your heating system from warming your living space as well as it should since your system is designed to operate on set heating cycles. And in the long-term, short-cycling can actually cause more problems, increasing the chances of a sudden and detrimental heating system breakdown.

Ensure that you call for furnace repairs as soon as you hear, or suspect, your furnace short-cycling. We’d like to help you avoid replacing the system before you really should need to.


This is never something to ignore, especially in the case of a gas-powered furnace and/or older heating system. This booming sound is likely due to delayed ignition in the burner assembly, typically caused by carbon particle buildup on the jets. The more particles build up, the longer it takes them to ignite with the system cycles on.

The jets that end up igniting late will have to burn through a large amount of gas at once, and this is what produces that booming sound. Ensure that you have a professional clear out your burner assemble if you notice this sound, as that should solve the problem.

We’ve described some of the most common noises to listen for above, but the truth is, if your furnace is making any unfamiliar sounds, it’d be a good idea to call in a pro to inspect. It’s always better to be safe than sorry!

For expert furnace service in Eugene, OR, contact Comfort Flow Heating today.

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