Depending on your loop's complexity. If it's free from any restrictions, D5 is very silent but as you add fittings and other components D5 has to overcome the pressure and staring to make level of noise. Mine has to go through ton of fittings and flow sensors blocks and I also have huge case so I hear some noise but not much, you can tweak the pump to your liking via voltage control.
Mine its It's fairly quiet at 2200RPM and slightly lover and higher but at lower then 1900RPM and above 3000 RPM is pretty loud. It's the complexity of your loop that dictates how quiet or loud your D5 will be but generally D5 is very quiet pump.
Last edited by NewUser16; 04-21-2019 at 05:49 AM.