Outdoor air is introduced into a dehumidification system after the evaporator coil for several reasons. During the winter cold outdoor air may cause condensation in return air at undesirable places in the system or ductwork. Also, the variability of the outdoor air will influence the design and performance of the evaporator coil. When colder outdoor air mixes with the return air from a poolroom, it lowers the mixed air conditions that flow over the evaporator coil. This lower condition reduces the capacity of the system and creates a variable, unpredictable moisture removal and cooling capacity. To eliminate these issues, Desert Aire’s outdoor air box introduces the outdoor air between the evaporator and hot gas reheat coil.