I voted that the 15K AC cools our RV OK; however:
1) If we've just gotten set up and it is hot it will take until sundown to get the inside even moderately cool;
2) If we are in the sun and it is quite hot, the AC will keep the inside tolerable, but not cool
3) It blows a lot of cold air, but sometimes not quite enough.
4) It is too darn loud.
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch