A climate treatment and air refreshing apparatus for a room located in a building , configured in single-piece form and bounded by an external chamber intended to be placed within the room, an outside air intake and exhaust , intended to be connected to the exterior of the building, being built onto said external chamber, wherein said apparatus comprises: - a first air circuit , comprising a first inlet and a first outlet ; as well as a first fan and a first air/coolant heat exchanger disposed between the first inlet and the first outlet; - a second air circuit , comprising a second inlet and a second outlet respectively disposed at the intake and exhaust; as well as a second fan and a second air/coolant heat exchanger disposed between the second inlet and the second outlet; - a third air circuit , comprising a third inlet independent of the first inlet, a third outlet leading to the second circuit between the second heat exchanger and the second outlet; and a third fan and a third air/air heat exchanger disposed between the third inlet and the third outlet; and - a fourth air circuit , comprising a fourth inlet leading to the second circuit between the second inlet and the second heat exchanger, a fourth outlet leading to the first circuit between the first heat exchanger and the first outlet; the third air/air heat exchanger being disposed between the fourth inlet and outlet, so as to enable a heat exchange between the air circulating in the third circuit and the air circulating in the fourth circuit ; the first and third air inlets and the first air outlet being disposed on the surface of the external chamber and intended to be located within the room; the first and second air/coolant heat exchangers forming part of a heat pump disposed within the chamber of the apparatus. - a first air circuit , comprising a first inlet and a first outlet ; as well as a first fan and a first air/coolant heat exchanger disposed between the first inlet and the first outlet; - a second air circuit , comprising a second inlet and a second outlet respectively disposed at the intake and exhaust; as well as a second fan and a second air/coolant heat exchanger disposed between the second inlet and the second outlet; - a third air circuit , comprising a third inlet independent of the first inlet, a third outlet leading to the second circuit between the second heat exchanger and the second outlet; and a third fan and a third air/air heat exchanger disposed between the third inlet and the third outlet; and - a fourth air circuit , comprising a fourth inlet leading to the second circuit between the second inlet and the second heat exchanger, a fourth outlet leading to the first circuit between the first heat exchanger and the first outlet; the third air/air heat exchanger being disposed between the fourth inlet and outlet, so as to enable a heat exchange between the air circulating in the third circuit and the air circulating in the fourth circuit ; the first and third air inlets and the first air outlet being disposed on the surface of the external chamber and intended to be located within the room; the first and second air/coolant heat exchangers forming part of a heat pump disposed within the chamber of the apparatus. <EOS>