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.