An air handling apparatus comprising: a first heat exchanger and a second heat exchanger; a first fan and a second fan; first and second fan compartments, and a central compartment, the first fan compartment includes the first fan, the second fan compartment includes the second fan and the central compartment includes the first heat exchanger, the second heat exchanger and a separation means, wherein the first fan compartment comprises at least one first fluid inlet connected to the central compartment and at least one first fluid outlet port connected to the first fan and the second fan compartment comprises at least one second fluid inlet connected to the central compartment and at least one second fluid outlet port connected to the second fan, and the central chamber comprises a first inlet port connected to the first heat exchanger and a second fluid inlet port connected to the second heat exchanger, the separation means is movable between a first and second position, characterised in that in the first position a first chamber is defined containing the first heat exchanger and the first fan, and a second chamber is defined containing the second heat exchanger and the second fan, and in the second position a first chamber is defined containing the first heat exchanger and the second fan and a second chamber is defined containing the second heat exchanger and the first fan, and wherein in the first position two distinct closed loop fluid pathways are defined in which in a first fluid pathway fluid flows through the second fan and the second fluid outlet port and re-enters the apparatus through the second fluid inlet port passing through the second heat exchanger and back to the second fan, and in a second fluid pathway fluid flows through the first fan and the first fluid outlet port and re-enters the apparatus through the first fluid inlet port passing through the first heat exchanger and back to the first fan, and in the second position a single loop fluid pathway is defined such that fluid flows through the second fan and out of the apparatus via the second outlet port, re-enters the apparatus through the second fluid inlet port passing through the second heat exchanger and through the first fan and first outlet port and then re-enters the apparatus again through the first fluid inlet port passing through the first heat exchanger. a first heat exchanger and a second heat exchanger; a first fan and a second fan; first and second fan compartments, and a central compartment, the first fan compartment includes the first fan, the second fan compartment includes the second fan and the central compartment includes the first heat exchanger, the second heat exchanger and a separation means, wherein the first fan compartment comprises at least one first fluid inlet connected to the central compartment and at least one first fluid outlet port connected to the first fan and the second fan compartment comprises at least one second fluid inlet connected to the central compartment and at least one second fluid outlet port connected to the second fan, and the central chamber comprises a first inlet port connected to the first heat exchanger and a second fluid inlet port connected to the second heat exchanger, the separation means is movable between a first and second position, characterised in that in the first position a first chamber is defined containing the first heat exchanger and the first fan, and a second chamber is defined containing the second heat exchanger and the second fan, and in the second position a first chamber is defined containing the first heat exchanger and the second fan and a second chamber is defined containing the second heat exchanger and the first fan, and wherein in the first position two distinct closed loop fluid pathways are defined in which in a first fluid pathway fluid flows through the second fan and the second fluid outlet port and re-enters the apparatus through the second fluid inlet port passing through the second heat exchanger and back to the second fan, and in a second fluid pathway fluid flows through the first fan and the first fluid outlet port and re-enters the apparatus through the first fluid inlet port passing through the first heat exchanger and back to the first fan, and in the second position a single loop fluid pathway is defined such that fluid flows through the second fan and out of the apparatus via the second outlet port, re-enters the apparatus through the second fluid inlet port passing through the second heat exchanger and through the first fan and first outlet port and then re-enters the apparatus again through the first fluid inlet port passing through the first heat exchanger.