I just remembered another issue with the AC. If yours is ducted through the ceiling you can improve its efficiency by blocking those ducts at the AC and purchase or fabricate a new return grille. The ductless grille is still available from Dometic but the filter is too restrictive.
Both cold air and return are squeezed through that 14 inch square hole under the AC unit. To make matters worse there is a six inch square metal junction box in the middle of that hole, further restricting air flow. Finally, the return air filter is an 8 X 12 piece of washable foam.
The ceiling ducts are highly pressurized to compensate for being grossly undersized. Each duct is about ten feet long with an internal cross section of about 12 square inches. Mine leak cold air into the ceiling cavity.
I am fabricating a new intake duct that will pull upward through a 14 X 14 pleated household filter and direct the cold air front and back in two streams along the ceiling. More filter area and the lack of ducts will improve air flow. The fan motor is quite large to compensate for the large pressure drop. With a better intake and no ducts you should get by with lower fan speed. The Dometic slide t-stat has two fan speed settings. The motor, however, has three.
I temporarily bypassed my ducts to see if there was a difference in AC on-time and it was substantial. The airborne and mechanical noise levels were also reduced.
The only disadvantage of ductless is that you will have to leave the bedroom door open to get cool air.
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