ScottG wrote:
Some of the newer bypass pumps aren't too bad.
Most of the noise comes from the plumbing vibrating against walls and what not.
If you can isolate the water lines where ever they touch anything (pipe insulation works great) you can reduce noise dramatically.
There are also "Quiet Kits" that add more flexible lines to the input and output and allow the pump to vibrate without transferring that to the harder pipes and anything they touch.
Some even put foam or rubber pads under the pump.
Thanks. About 10 years ago I put the pump on rubber mounts and wrapped it and the plumbing from it in dense foam. That cut the noise maybe just 20% or so. Needless to say I was disappointed in my effort . . .