I have an AirX. Having had a deck mounted diesel genset on my last boat, I have a theory:
The AirX puts out the same total amount of noise as the diesel genset, it just spreads it out over 24 hours instead of getting it all out in 1 hr.
For those math types, the summation of noise of the AirX over 24 hours is equal to the summation of noise of the diesel genset over 1 hour.