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HVAC Noise Demystified: Common Causes and Their Solutions

HVAC Noise Demystified: Common Causes and Their Solutions

With today’s smart HVAC systems, the only noise you should hear is just the gentle whoosh of cool air circulating in summer and cozy warmth in winter. Sometimes, however, other noises may occur.  Due to the design of smart HVAC systems, even small noises may be amplified and distributed throughout the house by the ductwork system. Therefore, they can be hard to identify and track back to their origin.

A qualified HVAC service professional is familiar with typical noises and can often quickly pinpoint the source and resolve the issue. Here are some causes of mysterious noises in your HVAC system as well as the usual cures.

  • Popping or banging noises inside the vents. Usually this occurs when the air conditioner or furnace is just starting up or has just shut down. Temperature changes cause metal ductwork to expand or contract, making popping sounds or muffled bangs. Typically the noise is short-lived and fades quickly. An HVAC contractor can discuss options to correct the problem.  
  • Squeaking or squealing. The blower in the indoor air handler incorporates moving parts that may squeak when the system is running. Usually it’s due to wear or lack of lubrication. Because the noise is typically transmitted through the ductwork, it’s origin at the blower may not be obvious. Blower  maintenance or replacement can restore quiet operation.
  • Roaring or rumbling noise. If the system is in heating mode, noises originating at the furnace burner may sound like roaring or rumbling. These sounds travel through the ductwork into individual living spaces.  This is a serious symptom that could indicate improper combustion at the furnace burner. Contact an HVAC professional immediately to report the issue.
  • Whistling sounds. Leaky ductwork is common as a house ages. Air passing through supply ducts under pressure may make whistling noises as it escapes through small leaks. A duct pressure test can identify the extent of duct leaks as well as pinpoint the locations for professional duct sealing.  

For diagnosis and repair of smart HVAC symptoms including unexplained noises, contact the professionals at Hansberger Refrigeration and Electric Company.