Normal Ductwork Sounds
Air Duct capacity is measured by the amount of air that can pass through them in cubic feet per minute (CFM). Circular ducts are the quietest because they have the most area and there's less air pressure on their surfaces. Rectangular ducts tend to create the most noise because their internal size is smaller and air pressure on their surfaces is higher.
Noise After Cleaning
Sometimes normally quiet air ducts will develop noises after being professionally cleaned. Removing all the dirt and debris from them removes the obstructions that slowed down the air velocity and make the entire HVAC system more efficient. When they're clean, the CFMs increase, and noise may result.
Noises That May Indicate Problems
Anytime you hear ductwork popping or banging near the air handler in the heating mode, it's a good idea to investigate it. Ask another person to help you by turning up the thermostat as you stand a few feet away from the air handler. The furnace should ignite within a few minutes. As it runs, listen for any booming sound coming from or near the furnace. This sound could indicate a clogged gas line going into the burner.
Call your HVAC professional immediately for cleaning. A clog in any of the gas supply lines going to the burner could cause an explosion or crack the heat exchanger.
Whistling from one or more of the air ducts usually indicates that the register covers may be too restrictive. Choose less restrictive vent covers or verify that the louvers for the existing covers are fully open and not blocked by furnishings. Do not turn down the fan speed to lower the CFM, since lower airflow may harm the furnace or air conditioner's internal components.
If you have unexplained duct noises, contact the pros at Air Control Heating & Cooling. We've provided outstanding HVAC services for Havana, Tallahassee and Quincy homeowners since 1`964.