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Duct Noises in Your Fairfax Home? How to Tell What They Mean


All HVAC systems produce noise, such as airflow whooshing from the outlets, the furnace igniting or the A/C compressor whirring away. There are certain noises that are not normal and indicate problems. If you’re hearing atypical duct noises in your Fairfax home, use this guide to find out what they mean and what should be done.

Rattling and Clamoring

Good duct design comprises correctly sized, sealed and insulated air ducts and connections that deliver conditioned or ventilated airflow to the living spaces. It sounds simple enough, but ductwork problems account for as much as 20 percent of energy losses in the average home, according to the U.S. Department of Energy (DOE).

Duct noises are key indicators that there are duct or HVAC issues that are costing money. Rattling and clamoring ducts are quite common. These noises often indicate loose duct connections. Since ducts are typically fabricated of sheet metal, the loose connections rattle and clamor and drain your pocketbook.

Banging and Booming

Air ducts may shift, expand or contract during a heat or cool cycle. This is normal, but it doesn’t make it any less bothersome. The change in temperature causes the metal ducts move, which may create bangs, booms and popping noises.

Duct Troubleshooting

Locating the problem ducts is the first troubleshooting step. If you notice uneven airflow from the supply outlets, you may have located a leaky or fallen duct connection. Visually inspect the ducts for loose connections, fallen ducts, damaged ducts and portions of ductwork with no insulation.

  • Loose and fallen ducts may be rejoined using metal tape and a paste or aerosol sealant.
  • Damaged ducts should be repaired or replaced by your HVAC professional.
  • If there are any uninsulated ducts, they should be insulated with rigid fiberboard or simply wrap them with fiberglass batts.
  • Booms, bangs and popping noises may be resolved by repositioning the ducts (a job for your HVAC pro) or installing acoustic dampers.

For assistance with duct noises, HVAC or plumbing issues in your Fairfax home, please contact us at HVAC & Plumbing Unlimited Heating & Air Conditioning. We proudly serve Fairfax, Loudoun and Prince William counties.

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HVAC Unlimited Inc.
Ned came out to inspect my HVAC unit. The company was very good and flexible about scheduling and Ned called before hand to give me an approximate arrival time which was very helpful. He was professional and polite and even though he had to deliver bad news he was helpful in explaining what the issue was and the options.
Jeff - Oakton, VA
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