Furnaces are an integral component of any highly functional HVAC system, as they are responsible for making and distributing heat throughout a home. Like many other noise-inducing parts of our houses, including the floors that creak and the air conditioners that hum, furnaces tend to make innocent sounds that we often ignore. But there are other sounds that should raise a red flag and trigger our immediate attention. How are we to discern between the sounds of normal furnace operations and the ones that only a highly-qualified technician should diagnose? Read on to learn about three furnace sounds that should never be ignored.


This sound is often characterized by a high-pitched squealing or screeching. Like rubbing metal, this sound indicates a problem with the blower wheel so the system should be turned off immediately. You could cause further damage by continuing to let the blower fan run. If you hear this grinding sound, it’s likely that the fan came loose from the motor shaft which requires urgent assistance from an HVAC technician. A quick and easy replacement is the common recourse, unless the whole assembly has been affected, which may require a more complex repair.

Loud bang or boom

An unsafe gas buildup may result in sounds that resemble that of gunshots or explosions. Always a cause for alarm, these frightening noises also indicate that an expensive repair is necessary. It’s important to immediately turn off the system, and get a licensed professional on-site. Regular seasonal maintenance can ensure this unnecessary buildup does not occur, avoiding costly repairs. In trusting the HVAC professionals at Canady’s to seal and insulate ducts and replace air filters with every seasonal transition, homeowners can rest assured that their furnace will remain optimized for safe use.


A distinctive rumbling sound indicates that a furnace hasn’t been maintained in a while. Distinguished from what some may describe as a banging or rattling sound, this growling noise is a sign of dirty gas burners or a pilot light that needs to be adjusted. Clean and efficient burners are usually blue, and, while a small yellow tip is fine, anything else requires immediate assistance from a qualified technician. The red, yellow, orange, purple, and green colors may indicate potential threats that should be attended to right away.

Stay Safe

Furnace noises may be cause for alarm or they may just be audible signs that the system is operating normally. It’s important to understand which sounds should trigger immediate action to ensure the health and safety of everyone in your home. Contact us to learn more about our seasonable HVAC services that will help you distinguish between excessively loud furnace sounds or the ones that simply remind you that a tune-up is necessary.