An air conditioning unit, which can be located in an enclosed environment comprising at least one duct through which a heat transfer fluid flows. The duct is affected sequentially by at least one compressor, for raising the temperature and pressure of the heat transfer fluid in the gaseous state, at least one condenser, for carrying off heat from the heat transfer fluid and its passage from the gaseous state to the liquid state, at least one lamination element, for lowering the pressure of the heat transfer fluid in the liquid state, and at least one evaporator, for absorbing heat by means of the passage of the heat transfer fluid from the liquid state to the gaseous state.The air conditioning unit comprises elements of natural, not forced, collection and conveyance, toward the condenser, of condensed water which may have formed along the outer surfaces of the evaporator.