I know how to identify them from if I open them but not by just looking at them from outside, please help me with the answer. thanks.
Since I start indoors (checking filter and such), I check the thermostat...
...EM Heat, AUX Heat, or two stage heat as indicated with two mercury switches are good indications that I have a heat pump system.
Maybe down south they don't elevate heat pumps ? Up here the deforst water would back up because the unit would be in snow. The FEW heat pumps that we were forced to sell were alway put at least 1 foot above the ground level.