Hair drying unit suitable for being installed in a room; said hair drying unit comprising an end device comprising a body (r1; r2; r3; 20; 30); said end device comprising a first conduit, a second conduit, at least one first opening (1a; 31, 21a) in communication with said first conduit and at least one second opening (1b; 32; 22a) in communication with said second conduit; said end device being suitable for being used in the vicinity of a user's hair; said hair drying unit comprising a heating/dehumidification system comprising: - a boxed frame comprising a first chamber and a second chamber; said boxed frame comprising a first connection inlet disposed in said first chamber and a second connection inlet disposed in said second chamber; each one of said connection inlets (b1, b2) being in fluid communication with one of the two conduits of the end device; said boxed frame comprising a first opening that puts said first chamber in communication with a room, and a second opening that puts said second chamber in communication with the room; - connection means suitable for putting said first connection inlet and said second connection inlet in fluid communication with the corresponding conduit of the end device; - a heat pump comprising components suitable for being crossed by a heat transfer fluid and disposed inside the boxed frame; said components comprise a condenser disposed in said first chamber, an evaporator disposed in said second chamber, a laminating unit and a compressor; - a first bi-directional electric fan disposed in said first chamber and a second bi-directional electric fan disposed in said second chamber; said electric fans (V1, V2) being configured in such a way to generate airflows that circulate in the boxed frame; - a control unit connected to said electric fans (V1, V2) to deactivate or activate said electric fans (V1, V2) by rotating them in either direction in such a way that the following is generated in the boxed frame: a) an incoming airflow that passes through the second connection inlet and is conveyed towards the evaporator, and an outgoing airflow that passes through the condenser and passes through the first connection inlet; or b) an incoming airflow that passes through the first connection inlet and is conveyed towards the condenser, and an outgoing airflow that passes through the evaporator and is conveyed into the second connection inlet. - a boxed frame comprising a first chamber and a second chamber; said boxed frame comprising a first connection inlet disposed in said first chamber and a second connection inlet disposed in said second chamber; each one of said connection inlets (b1, b2) being in fluid communication with one of the two conduits of the end device; said boxed frame comprising a first opening that puts said first chamber in communication with a room, and a second opening that puts said second chamber in communication with the room; - connection means suitable for putting said first connection inlet and said second connection inlet in fluid communication with the corresponding conduit of the end device; - a heat pump comprising components suitable for being crossed by a heat transfer fluid and disposed inside the boxed frame; said components comprise a condenser disposed in said first chamber, an evaporator disposed in said second chamber, a laminating unit and a compressor; - a first bi-directional electric fan disposed in said first chamber and a second bi-directional electric fan disposed in said second chamber; said electric fans (V1, V2) being configured in such a way to generate airflows that circulate in the boxed frame; - a control unit connected to said electric fans (V1, V2) to deactivate or activate said electric fans (V1, V2) by rotating them in either direction in such a way that the following is generated in the boxed frame: a) an incoming airflow that passes through the second connection inlet and is conveyed towards the evaporator, and an outgoing airflow that passes through the condenser and passes through the first connection inlet; or b) an incoming airflow that passes through the first connection inlet and is conveyed towards the condenser, and an outgoing airflow that passes through the evaporator and is conveyed into the second connection inlet. a) an incoming airflow that passes through the second connection inlet and is conveyed towards the evaporator, and an outgoing airflow that passes through the condenser and passes through the first connection inlet; or b) an incoming airflow that passes through the first connection inlet and is conveyed towards the condenser, and an outgoing airflow that passes through the evaporator and is conveyed into the second connection inlet.