Not long ago I installed some Tubular Pipe Insulation on the the water pump lines coming in & out of the water pump. I tested the results and my somewhat poor hearing suggested that the sound from the water pump was quieter. So today, while Margee and I were piddling in our LD and I asked her to listen to the water pump. She remarked that the pump had a softer, muffled sound. We're pleased to have a calmer sounding water pump.