I recently bought a Carrier 13,500 for a 21' Chinook Concourse class b. ----- It cools fine but is very ex ceptionally loud. infact, more so than the 3 speed 20 year old Dometic I replaced. You'd think that in 20 yrs. they could have solved the noise problem. Also carrier touts it's 2 speed model as quiet and state of the art. allot of balony. Tried to contace carrier for support / advice and rec. no reply.