What Those Duct and Furnace Noises are Trying to Tell You

Troubleshooting Furnace and Duct Noises

If your furnace or ductwork (or both!) have a lot to say, you may want to investigate their babblings to ensure there’s nothing going on that require professional attention. While some noises emanating from the ducts and furnace are perfectly normal and nothing to worry about, others can indicate serious problems that need fixing sooner than later.

Common noises that you may hear coming from the ductwork include:

Popping Sounds

POP! Popping noises are very common and perfectly normal. They occur when the metal ducts expand and contract as they fill with air and then empty. There’s not a lot you can do about these noises, but if they’re particularly loud, it may be the hardware holding the ducts in place that are making the noise, and you can slide little pieces of wood or rubber between the hardware and the surface it’s attached to in order to reduce these noises.

Whistling Noises

WHISTLE! Whistling noises or high-pitched tuning fork sounds usually indicate a problem with airflow, which can damage your furnace or air conditioner, increase your energy bills and the wear on your system, and reduce your comfort level.

Check the Filter & The Return Vents

Check the furnace filter first, and if it’s dirty, replace it with a new one. If the noise persists, check to ensure all supply and return registers are open and unobstructed. If the noise continues, you may have undersized or poorly designed ductwork, and you may have to live with it until it’s time to replace the ducts. If the noise is accompanied by reduced airflow at the supply registers or unusually high energy bills, it’s a good idea to have an HVAC technician out to assess the system and determine the problem.

Rattling or Flapping Noises

RATTLE! FLAP! It sounds like you may have little green army men, marbles, or other tiny toys trapped in your ductwork. Kids love shoving all manner of flotsam and jetsam into the return and supply registers, and the noise can drive you to distraction. Unless you can reach the offending objects, it may be time to call in a professional to clean out your ducts.

Common noises that you may hear coming from the furnace include:

Booming Sounds

BOOM! Quiet booms can probably be attributed to the expanding of the plenum (the warm air storage box on top of the furnace) as it fills with air, and are likely nothing to be worried about. Loud, frequent booms are another story. Dirty burners or delayed ignition can cause loud booms, which, alarmingly, is the sound of small amounts of gas exploding after building up, waiting for the burners to do their job. Call your HVAC professional right away if you hear loud booms coming from your furnace.

Rumbling Sounds

RUMBLE! Rumbling sounds usually indicate a dirty heating element or a cracked heat exchanger and warrant a visit by an HVAC technician.

Screeching Sounds

SCREECH! Ear-splitting screeching noises that make you wonder if a banshee has taken up residence in the furnace are usually attributed to a faulty blower motor, belt, or bearings, and you’ll need to have someone out to remedy the situation ASAP or risk further, more serious problems.

Maintenance Is Key

Annual preventive maintenance on your furnace will go a long way toward preventing the problems that cause these noises, and it’ll help ensure lower heating bills, a longer life for your equipment, and a higher level of comfort.

For more expert tips on diagnosing furnace and duct noises, contact us at Comfort Control, Inc by callng (770) 999-9658 today!

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