My Furnace is Making a Rattling Noise

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My Furnace is Making a Rattling Noise


Modern furnaces operate very quietly, especially when considering how they used to be one of the noisiest units in a home. These days they only create small, fairly unobtrusive background noise for homeowners. If you catch yourself thinking, “my furnace is making a rattling noise,” you’re likely dealing with an underlying issue that’s creating sounds beyond what’s considered normal.


Strange noises coming from your furnace are early warning signs that a repair is needed, so don’t hesitate to contact your HVAC repairman. The faster the problem is professionally repaired, the fewer repercussions you’re likely to face. 

Top Reasons Why My Furnace is Making a Rattling Noise

Rattling is a fairly common warning sound in furnaces, though the cause can vary. In some cases, rattling can indicate something as simple as a loose bolt in the access hatch, while in other cases, the root issue could be far more serious. 


Here are some possible reasons why your furnace is making a rattling noise.

Cracked Heat Exchanger

A heat exchanger is a group of coils within your furnace that are heated using either gas, oil or electricity. When cold, winter air blown is drawn into your furnace, it blows over the heat exchanger, where the heat then transfers from the coils to the air, resulting in heated air throughout your home. A cracked heat exchanger—which can happen due to the age of your furnace, restricted air flow, or by having an oversized furnace—often results in a rattling noise, particularly when the furnace first kicks on. 

Misaligned Blower

As you may have guessed from its name, the blower is responsible for blowing unconditioned air over the heat exchanger and into your home’s ductwork. The parts holding the blower in place within your furnace can become loose over time, causing misalignment that leads to a rattling noise when the furnace is running. If the blower isn’t properly secured in place, the constant shaking and vibrating against other elements within the furnace can lead to greater damage to the blower later on, which may result in costly repairs. 

Loose Connections, Panels, or Screws

With prolonged use, the connections, panels, or screws within your furnace can become loose. You may also notice some loose hardware if you’ve recently had work done on your furnace. Try to identify the source of the rattling by checking your furnace’s access panel, ductwork connections, and any other easily viewable screws. While you can tighten the access panel or exterior screws yourself, internal connection issues require the attention of a professional

Dirty Burners

If you have a gas furnace, then you likely have some type of burner system in your furnace. While you never want to tamper with these yourself, dirty burners could be the cause of the rattling noise you’re hearing. A professional HVAC specialist will need to safely remove the burners, clean any dust or dirt, and then inspect your unit for any additional debris. 

Fix Furnace Rattling Today

If your furnace is making a rattling noise, turn to CroppMetcalfe's 5-Star Technicians for the expertise you need. CroppMetcalfe offers heating installation, repair, and maintenance services for a variety of heating systems including furnaces. 

Call CroppMetcalfe now or schedule a service appointment online today!



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