A purge section is typically used to reduce the carryover of contaminants in enthalpy recovery wheels. A one-dimensional transient heat and mass transfer model is developed to analyze the performance of enthalpy recovery wheels both with and without purge air. The governing equations are coupled, and the variables are solved using a trial and error method. The enthalpy recovery wheel model without purge air is validated using previously published results with good agreement. Finally, the results of an enthalpy recovery wheel with purge air are presented, and indicate that there is an optimum wheel depth and rotation speed to achieve maximum performance for enthalpy recovery wheels with purge air. (C) 2012 Elsevier Ltd. All rights reserved.