I currently am in the Los Angeles Ca area, my 2014 366FL currently only has the one 15k AC unit above the kitchen. this summer when it was in the triple digits outside it was only a few degrees cooler inside (90's), after I sealed all the open connections in the duct work and above the AC filter I managed to get it to cool the living room and kitchen about 20 degrees cooler, maybe this winter I will install another AC unit in the bedroom, it's already pre wired for it. I haven't decided to go with a 13k or 15k unit. I am strongly looking toward another 15k unit, as hot as it gets here, for the difference in price it may not be a bad idea. any thoughts?