I had the 5000BTU window AC installed in the 13' 2008 Scamp
in the closet a year after I bought Scamp
(used). The first summer I had Scamp
, I went to Lake Mead, NV in July camping/kayaking. It was over 110 degrees during the day, and did not get below 95 at night. The fan was going full blast and all the windows were open. Never want to try to sleep in weather like that again. After that trip I thought, go north in the summer and south in the winter. That limits where I could travel, when. It was worth it to me to have the AC installed. The initial cost was less than a roof AC replacement. But, if the AC ever breaks down, I can go to Lowes/Home Depot/WalMart/Target, etc. and get a replacement for $100 and put it in myself in under an hour. I'm not sure what the cost would be to retro fit the roof with reinforcement and add the AC. The roof AC unit alone is around $900. The cost/benefit ratio is subjective to individual preferences. It would not hinder the resale value unless the buyer would never use it or the roof leaked.