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HVAC System Noises and What They Mean


Generally, the HVAC system produces some sounds when running, such as a quiet hum of air whooshing through the air ducts. Disruptive noises are a tell-tale sign that something is not right with your HVAC system. Below are common HVAC noises and what they mean for your Marietta, GA, home.


Your HVAC system producing a rattling sound could mean a few things. If the sound comes from the outdoor unit, there are chances that your system has debris, such as twigs. Although the grate effectively protects against large debris, small things can still go through.

Turn off your system and cut the power to the unit immediately you notice the noise. Try and remove the debris, but if there is any visible damage to the compressor, fan, or fins, call in the HVAC professionals. If the rattling comes from inside the house, ensure that the system is immediately inspected.


It is normal for the HVAC system to produce a soft humming noise. But if the humming becomes almost similar to clanking, then something is not right. The noise could be due to loose parts, such as fan blades or loose pipes, that are rubbing against each other.

Circuit breaker overload, loose wiring, or a failed condenser fan motor could also produce your loud humming noise. Loose parts can quickly lead to costly damages to your HVAC system. A good practice is to turn off the system and inform your technician immediately.


A hissing sound from the HVAC system is often an indicator of air escaping from the system. There is a good chance that your air ducts are leaking if the noise comes from the walls. This reduces the efficiency of the system in cooling your home.

Call in the experts since duct repairs isn’t a job you can do on your own. Also, check if the air filter fits properly since any gap in the seal can result in a hissing sound.

Contact E. Smith for the best HVAC repair and installation services to ensure that your system runs smoothly. Call us today to have your system repaired or serviced professionally.

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