Heated air should enter a room from a source or opening down low in the room.
The warmed air from an air conditioner operating in heating mode with it's heat strip and fan turned on and compressor turned off most likely enters an RV from an opening up high - not good. Only chilled air should enter a room from an opening up high - where most RV heat pumps in cooling mode and RV air conditoners have it coming from for best cooling efficiency in hot weather.
HOWEVER from the viewpoint of raw BTU creation efficiency for heating an RV, an RV with a heat pump unit operating in it's heating mode instead of an air conditioner unit with it's heat strip turned on - uses far less electricity (around 1/3) to produce 5000 BTUs than a portable electric heater or heat strip in an air conditioner does to produce their 5000 BTU output (a 1500 watt electric heating element produces around 5000 BTUs). This is because the heat pump process is way different (although it's electrically powered) than using electricity to directly make a heating element glow red.
All things considered and if the outside temperature is around 40 degrees or higher, an RV heat pump unit operating in it's heating mode will use less electricity than an air conditioner with a heat strip or a portable electric heater.
