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Home » Why Is Your Furnace Making Noise?

Why Is Your Furnace Making Noise?



When the weather in Upstate NY turns cold, you want to be warm, cozy, and trust that you can rely on your furnace to keep it that way!

A properly installed, updated heating system is designed to be as quiet as possible. Most furnaces (especially older ones) produce some level of banging and knocking, especially when they first start up or shut down. This is usually nothing to worry about.

How do you know what furnace sounds are normal, and which are not?

It’s important to remember that not all furnace noises are an emergency or need immediate attention. There are plenty of common causes for strange sounds coming from your furnace.

  • One of the most common is when the furnace is trying to start up. This can often be heard as a rattling noise.
  • Another common cause of noise is when the fan blades inside the furnace start to wobble, which can cause a whistling noise.
  • Finally, many furnaces will make noise in the winter when they switch over to heating mode. This is known as “banking,” and it can cause a variety of different sounds including rattling or ticking.

What Is That Furnace Noise?

If your furnace is making some odd, annoying or alarming sounds, you may have a problem. Here are some kinds of noises you may hear and potential causes:


There are several possible causes of this problem, including a dirty filter, a malfunctioning blower, or a problem with the furnace’s heat exchanger. The moving parts inside your furnace may rattle or clang together if they aren’t properly aligned.  If your furnace is making a rattling noise, it’s important to have it inspected by a qualified technician to determine the cause and fix it.

Ticking or Clicking:

Some older furnaces have capacitors that help start up the system. If these capacitors are dying, they may cause a ticking or clicking noise. This is not usually harmful, but it’s best to have your capacitor fixed if possible


If you live in an older home, it’s likely that your furnace has begun to make noise. A whistling noise can sometimes be caused by air passing over warped fan blades. Again, this is not an emergency, and you probably won’t need to fix it immediately if there aren’t any strange sounds coming from the machine itself.


Your furnace may make strange noises when started if some of its moving parts aren’t properly assembled. Usually this means that there is something wrong with the fan belt or the motor itself and should be serviced immediately to increase the lifespan of your system.

Cracking and popping:

Furnaces that use natural gas are designed to make a popping sound when the flame ignites. This harmless noise sounds like popcorn popping (hence the nickname). If you hear loud cracking or snapping sounds coming from your furnace, it’s possible that debris is stuck in the heat exchanger or burners. We recommend turning off the power switch to the furnace and checking for any obstructions before trying again.

Furnaces can last up to 25 years, so if yours is aging out, there is a good chance the noise you hear during operation is coming from the burner assembly or the blower motor.

The burner assembly often makes a high-pitched whistling sound when combustion efficiency diminishes because of deposits or cracks in burners. The blower motor has thin blades that are susceptible to motor damage. Whirring, rattling and vibrating noises are also potential sources of annoying sounds with furnaces. Let our experienced technicians check this out and let you know what action you should take if any.

What to do?

Making sure that your furnace is properly adjusted is another good way to keep strange noises at bay. If you have heard a rattling or whistling noise coming from your furnace lately, make sure you have it tuned up right away. A poorly adjusted system can grind parts together and cause all sorts of damage over time—not to mention the added stress on your family!

If you are having trouble discerning between harmless noises and ones that indicate more serious problems, it might be best to contact the professionals for help. Jack Hall Plumbing and Heating technicians will come out and fix any problems (or at least let you know what’s wrong) very quickly.

If your furnace is making sounds that alarm you, or stops functioning altogether, we are available for 24-hour emergency service in Glens Falls, Lake George, Queensbury, Saratoga Spring and the surrounding region when you need it! Call (518) 792-7114 to shedule an appointment. Jack Hall Plumbing has been in business since 1984, family owned and operated for 3 generations.

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