A quick demo of the sound output from this bath fan. I quickly (temporarily) mocked it up to hear it before I rip my ceiling apart and install it. It is pretty quiet, especially at the lower CFM setting. There are two settings, 110 and 80. The 80 CFM is under .3 sone and at 110 is is .5 sone (according to the box). I wanted to hear it, and compare it to my standard portable fan.