An air conditioner and a control method for the same, the air conditioner including an air conditioning unit including a compressor, a first heat exchanger, an expansion valve, and a second heat exchanger; and a controller configured to obtain enthalpy of a refrigerant flowing in the air conditioning unit, obtain an air conditioning capacity using a circulation amount of the refrigerant and the obtained enthalpy of the refrigerant, obtain efficiency based on the obtained air conditioning capacity and supplied power, and control the air conditioning unit according to the obtained efficiency.