I would like to make a change to my AC units so they are not so noisey. I have heard that the noise comes from obstructions in the air flow. I have also heard of people redoing the ceiling vents so ...
We set the very front air in the living room to come on at the tempurature we are comfortable with when going to bed. Then set the rear higher a bit. This way the front comes on first and keeping us cool without the noise in the bedroom area.