I have a 27RWL and it came with one ducted AC. It just could not keep the trailer cool enough during the summer. It would cool off ok at night but during the day it was just too hot. Soooo I added a 2nd AC, in the bedroom. Now you could hang meat in the trailer! The new unit isn't ducted, it dumps into the room.
Installing the AC was easier than I expected. Hardest part was getting the unit on the roof.
My advice is to have the AC inspected if you think it's not working correctly. If it is then you will want to add a 2nd unit. Best wishes and stay cool bro!
2015 Flagstaff 27RLWS Emerald Package
2013 Ford F150 STX 5.0 V8 3.55