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Comfy Heating & Air Conditioning Inc. Blog

Strange Furnace Noises, Explained

woman-covering-her-earsWe may not experience the frigid temperatures that our friends in the Midwest do, particularly lately, but our winters still necessitate the use of a fully functioning, efficiently operating, heating system. So if your heating system is experiencing problems right now, we understand the concern! Fortunately, though, if you can detect problems with your furnace early enough, you can have them repaired before they develop into a complete system breakdown.

However, you need to be particularly vigilant if you want to catch these problems early enough. If you’re reading this blog post, then you’re already on the right path! After all, one of the first signs that something is, in fact, amiss with a heating system is the presence of strange noises while the system is in operation. Keep reading for a description of some of these noises and what they mean, and be sure to make your next step calling in a pro for repairs!


Is your furnace making a loud “booming” sound each time it starts up? Then you are probably experiencing a problem with delayed ignition. As the burner assembly in a gas furnace combusts fuel, carbon particles build up on the jest. While this may start out as harmless, over time that buildup will become severe enough that it will cause some of all of the jets to fire later than they’re supposed to.

When the jets do ignite, they burn through an excess of gas all at once. This is what causes that booming sound that you hear. Professional cleaning will clear out the burner assembly, and will resolve this issue. Be sure to get this on your schedule soon, though, as a clogged up burner assembly can eventually stop igniting altogether. This is a safety feature of your furnace, but not a convenient feature when you need your furnace the most!


There is a component inside your furnace called the air handler. This is the part that actually blows conditioned air around your living space while the system is operating. The air handler’s motor contains bearings that help reduce friction on the component while it is working. These bearings are designed to last quite a while, but they do wear down over time.

As this occurs, the friction on your air handler motor increases, until it begins emitting a grinding sound. If you hear this, is a good idea to call for repairs as soon as possible. If the bearings aren’t replaced in time, the motor could burn out altogether. It’s a lot more expensive to replace the air handler motor than to replace the bearings in that motor!


Do you hear your furnace turning itself on and off rapidly, without seeming to complete a full heating cycle? It’s time to call in a pro! This behavior is called short-cycling, and it isn’t something you want to continue.

Short-cycling speeds up the rate at which the various components of your furnace begin wearing down, making breakdowns more likely to occur. If this problem is allowed to continue long enough, it can shorten the lifespan of the furnace by years. Call us for repairs as soon as you notice your system doing this.

For professional heater repair in Danville, CA, contact Comfy Heating & Air Conditioning Inc. today!

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