RV industry has been ripping people off with poor products for years, at least they use to last!
First they chop a hole in the living area ceiling, then they put a motor, fan and compressor in the hole, directing the noise into the living area. Absolutely brilliant.
So now you have a vacuum cleaner running in the RV powered by a lawnmower under the unit!
For my Toyota I modified a window AC to fit on the roof. In my new to me Roadtrek I installed a LG9500 inverter AC, this AC is wonderful especially at night in sleep mode! The Roadtrek is designed for a window AC.
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/21943313/print/true.cfm