The reason I am replacing the A/C unit is because of clearance issues where I store the trailer not with the unit itself. I bought the trailer knowing I would be replacing the A/C unit with a low profile the same thing I had to do with my old trailer. What my real question is there a formula or something that tells you if you have a trailer with a 8'x22' box and well insulated with fiberglass outside walls what size do you need to cool it if outside temperature is 90 degrees? I think the OEMs install 13.5K in all their trailers from their smallest to 26' due to bulk buying rather than that is what is needed. Just my two cents.