timmmay:It's definitely loudest when it's first on, it seems to be on fan setting 4/5 initially. Just keeping the room warm it seems to go down only one notch to 3/5, and sometimes not even that low. I manually set it to lowest fan position and it's pretty good, and if you set it to silent it is really quiet, but I wonder what it does to the efficiency.
You may also want to check how "smart" (meaning dumb) the controller is, for example with some systems if you set them to maintain, say, 21 degrees then they'll pump out hot air at max rate, overshoot, pump out cooler air to correct, overshoot, pump out hot air again, and so on, all at a high volume and noise level. You'd need to either read your manual or experiment to find the quietest set of settings if your system isn't that smart. For example my older Mitsubishi has multiple semi-overlapping and inconsistent modes, all illustrated with incomprehensible icons, most of which are differentiated only by the level of noise they make. The starry-icon mode (whatever one that is) is the best one, it's heat-only so it doesn't care if it overshoots, it just stops heating for awhile if it gets too warm. That's the lots-of-noise-initially, then occasional-boost mode I referred to earlier.