The introduction of high-efficiency desiccant rotors with the possibility of being regenerated by low-temperature heat offers new opportunities to the desiccant technique in the field of air conditioning. The use of energy recovered from the condensers of the chillers or from CHP units to obtain humidity control in buildings involves a remarkable fall in the energy and operating costs for air conditioning especially in a mild climate. The reduction of installed cooling capacity is also important. The performance of air handling units that include these drying wheels are here compared with those of traditional solutions, both in energy and economic terms. The results are very promising. Copyright (C) 2001 John Wiley & Sons, Ltd.