I have another host right across the street from me with a Class A. He obviously has a heat pump, actually two, and I can tell when they are running from across the street. I don't hear them when I'm inside, but outside it is very obvious.
Of course in the summer when everyone is running 1 or 2 a/c's including me I don't even notice the bit of noise when outside.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof