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AllTech Services, Inc. Blog

Call Us If Your Furnace Makes These Noises

woman-covering-her-earsWith the holiday season approaching and the hustle and bustle that goes along with it, it’s really easy to ignore subtle noises coming from your furnace. But we really have to urge you to stop and listen. Are those noises anything beyond the normal sounds of the system starting up, ductwork fluctuating, or air rushing through the vents?

If you’re hearing sounds you never have before coming from your heating system, it means there is a problem. Strange or unfamiliar furnace noises should never be ignored—but are there certain noises you should be concerned about more than others? Any unusual noise is cause for concern, but the following are particularly ominous:


Inside your heating system, there’s 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 bearing to keep friction as low as possible.

These bearings do a fantastic job of keeping that friction low, however, they do eventually wear out as a natural part of wear and tear. The more worn-out the 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, your air handler’s motor may overheat and burn out.


Does it seem like your furnace is turning on for shorter periods of time, to rapidly shut off and start back up again? This rapid cycling has a specific name—short cycling. This has a number of potential causes but the result is ultimately the same—heat gets trapped within the system and causes subsequent problems for your heater. This might be due to either an electrical issue, a clogged air filter, or perhaps even 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. This will create long-term problems for your furnace, increasing the chances of a sudden and detrimental system breakdown.

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


This is never a sound you want to ignore, particularly if we’re talking about a gas-powered furnace and/or aging heating system. This booming noise is likely due to delayed ignition in the burner assembly, usually caused by carbon particle buildup on the jets. The more particles build up, the longer it takes them to ignite when the system cycles on.

This might sound benign, but what happens is the jets end up burning through a large amount of gas at once (which creates the booming noise you hear) and causes your system to rattle. This eventually can lead to cracked heat exchangers—and when your heat exchanger is cracked it can and will leak dangerous carbon monoxide gas into your home.

The best thing you can do for your heater and for your home when you hear booming or any other strange noise coming from your furnace is to shut it off and call for professional repairs.

Contact AllTech Services, Inc. for professional heating services in Ashburn, VA.

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