I have a new 2011 big Country 3500RL. I am currently in Quartzsite AZ. The temp yesterday was 86 and the 15000btu ac had a real hard time keeping the trailer cool enough. The air temp comming from the vents seemed cool but I have my doubts that one 15000 ac will cool this big of a unit especially since it is dark grey in color and soaks up a lot of sun. I finally went outside and sat in the shade. It was much cooler. Anyone else have a similar problem???