Only once have I heard an A/C so noisy it was impossible to sit outside and talk! it was the rear unit on a Class A. the neighbors were running it full blast (fortunately they left 2 days after we arrived). it sounded as if the fan blade for the condenser was hitting the shroud! it was so loud everyone around us complained about it. they just didn`t get it, and people did say something. I was ready to go over and trip the breaker at the pedestal, except I was worried the generator may have been louder. BTW, this unit was only a few years old!