A double flow air-handling unit for thermal regulation and air renewal of at least one zone to be treated, said double flow air-handling unit being a desiccant air-handling unit that includes at least: - two air flow paths between the zone and the outside, comprising a return path and a blowing path; - a return fan placed on the return path to extract stale air from the zone and reject it to the outside; - a blowing fan placed on the blowing path to draw in fresh air from outside and blow it into the zone; - a desiccant wheel interposed on the two air flow paths (20R, 20S); - a recovery heat exchanger interposed on the two air flow paths (20R, 20S) and providing a heat exchanging between the stale air extracted from the zone and the fresh air drawn in from outside; - a regeneration heat battery placed on the return path upstream of the desiccant wheel and downstream of the recovery heat exchanger, and providing heating of the stale air for a regeneration of the desiccant wheel; - a blowing humidifier placed on the blowing path downstream of the recovery heat exchanger; - a heating heat battery placed on the blowing path downstream of the recovery heat exchanger; - a heat generator in connection with the regeneration heat battery and with the heating heat battery; said double flow air-handling unit being characterized in that it further comprises an enthalpy heat exchanger interposed on the two air flow paths (20R, 20S) between the recovery heat exchanger and the zone, so that the blowing humidifier and the heating heat battery are downstream of the enthalpy heat exchanger on the blowing path, said enthalpy heat exchanger providing a heat and humidity exchanging between the stale air extracted from the zone and the fresh air blown into the zone. - two air flow paths between the zone and the outside, comprising a return path and a blowing path; - a return fan placed on the return path to extract stale air from the zone and reject it to the outside; - a blowing fan placed on the blowing path to draw in fresh air from outside and blow it into the zone; - a desiccant wheel interposed on the two air flow paths (20R, 20S); - a recovery heat exchanger interposed on the two air flow paths (20R, 20S) and providing a heat exchanging between the stale air extracted from the zone and the fresh air drawn in from outside; - a regeneration heat battery placed on the return path upstream of the desiccant wheel and downstream of the recovery heat exchanger, and providing heating of the stale air for a regeneration of the desiccant wheel; - a blowing humidifier placed on the blowing path downstream of the recovery heat exchanger; - a heating heat battery placed on the blowing path downstream of the recovery heat exchanger; - a heat generator in connection with the regeneration heat battery and with the heating heat battery; said double flow air-handling unit being characterized in that it further comprises an enthalpy heat exchanger interposed on the two air flow paths (20R, 20S) between the recovery heat exchanger and the zone, so that the blowing humidifier and the heating heat battery are downstream of the enthalpy heat exchanger on the blowing path, said enthalpy heat exchanger providing a heat and humidity exchanging between the stale air extracted from the zone and the fresh air blown into the zone.