Effectiveness correlations are presented which allow the designer to predict the sensible, latent and total effectiveness of energy wheels when the operating conditions are known. The correlations agree with simulation data within +/-2.5% for sensible, latent and total effectiveness when the desiccant coating on the energy wheel has a linear sorption curve. The sensitivity of the sorption curve and operating condition factor are studied and the use of the design correlations is shown with an example.