The source of duct-system noise may be difficult to pinpoint. Ductwork naturally expands and contracts with temperature changes of the conditioned air. This is normal, but it doesn’t make noises any less annoying. Whether it’s an ongoing problem, new installation, or perhaps you’ve moved into a new home, there are specific causes of duct-system noise that can be identified as follows:
- Ducts are located too closely to wood framework, pipes or other objects.
- Inadequate connection at the duct trunk and the plenum.
- Loose or disconnected ducts.
- A house has settled/shifted over time which causes stress to ducts.
How To Fix Duct-System Noise
You have a few options to fix noisy ducts. For duct noise caused by contact or friction between the ducts and other objects, you may try the following:
- Install padding or insulation at the point of contact. This may reduce the noise enough so that it’s not an annoyance.
- Ducts should be installed one to two inches away from framework, pipes, and other objects. If your duct-system noise is from contact at multiple points because of poor installation, a heating and cooling professional will need to assess the best remedy for this problem, which may be either cutting away at framework, or readjusting ductwork.
For duct noise caused by expansion and contraction without contact, try the following:
- A common place for duct noise (“booms” and “bangs”) is at the duct trunk and plenum connection. This is near the heat exchanger, so there is great expansion and contraction in the ductwork. Install an expansion joint collar to reduce the stress.
- Duct stress and noises can be located anywhere in the system, often from a house settling and shifting over time. Acoustic duct liners may fix or muffle sounds of duct branches.
- Rattling and clattering is a sign of loose or disconnected ducts that should be sealed immediately with aluminum tape, or mastic.
If you would like a heating and cooling pro to inspect your ducts, call Paschal Heat, Air & Geothermal. We provide residents in the northwest Arkansas region with top service and care — and we have for 40 years.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about duct-system noises and other HVAC topics, download our free Home Comfort Resource guide.