Ducts and Furnace Noise: What They’re Communicating

January 30, 2015
Ross and Witmer

Your Mecklenburg home is far from silent, even when it’s empty: clocks tick, refrigerators hum, and HVAC equipment runs as needed. When it comes to duct and furnace noise, most sounds aren’t cause for alarm, but if they’re bothersome, you may want to consider having them fixed. Read on to find out more about some common noises you may experience, and what, if anything, can be done to silence them.

Duct Noise

Ducts come in a variety of shapes, including circular, rectangular and square. Their shape determines the amount of air pressure — measured in cubic feet per minute (CFM) — they can handle, with circular ducts taking the lead, square second, and rectangular in last place. This means that rectangular ducts are more likely to make a popping noise when placed under pressure, and while annoying, the sound isn’t dangerous, just a sign that there’s sufficient pressure inside them to cause expansion.

Options for reducing this type of noise include replacing the ductwork with circular or square material, or increasing the gauge of metal used. A simpler, and less expensive option is to have the manufacturer include a “crease” or “bend” in the long side of the ducting, to increase the strength on that side, and allow the ductwork to withstand greater amounts of pressure before they pop.

Furnace Noise

A pop or boom noise when the furnace comes on may indicate a delayed ignition, when one or more of the burners in the burner assembly becomes blocked or rusty. While initially failing to ignite with the others, once a sufficient amount of gas has entered the furnace, the faulty burner may catch as the result of a small explosion, resulting in the popping noise. If you suspect this issue, call in a professional for service.

For information or assistance with duct and furnace noise, call the experts at Ross & Witmer. We’ve been providing quality service to homeowners in Charlotte and the surrounding areas since 1945.

Leave a comment


Recent Posts