In this video, This Old House plumbing and heating contractor Richard Trethewey explains how to quiet a noisy forced-air system.
Steps for quieting a noisy forced-air system
- Mark center of start collars on the return and supply side of the heating duct.
- Cut holes in sheetmetal ducts using a drill fitted with a circle-cutting jig.
- Attach start collars to duct with ¾-inch self-tapping sheetmetal screws.
- Install bypass damper between the two start collars; fasten damper with sheetmetal screws.
- Seal seams around start collars with foil tape.
- Adjust the counterbalance weight on bypass damper arm.
- Turn on furnace to ensure bypass damper opens.