The present study proposes a new reduction method to calculate the heat and mass transfer characteristics of the wavy fin-and-tube heat exchangers under dehumidifying conditions. For fully wet conditions, the sensible heat transfer and mass transfer characteristics are relatively insensitive to the inlet relative humidity. The heat and mass transfer performances show appreciable influence of fin spacing at 1-row configuration. Both the heat and mass transfer performances increase when the fin spacing is reduced. However, the difference becomes less noticeable when Re-Dc > 3000. For 1-row configuration, larger wave height shows much larger difference with the fin spacing. However, the effect of inlet conditions and geometrical parameters on the heat and mass performance becomes less significant with the rise of number of tube rows. Test results show that the heat and mass transfer analogy is roughly applicable (the ratios of h(c,o)/h(d,o)C(p,a) are in the range 0.6-1.1, and is insensitive to change of fin spacing). The correlations are proposed to describe the heat and mass transfer characteristics. These correlations can describe 94.19% of the j(h) factors within 15% and 83.72% of the j(m) factors within 15%. Correspondingly, 93.02% of the ratios of h(c,o)/h(d,o)C(p,a) are predicted by the proposed correlation within 15%. (c) 2005 Elsevier Ltd. All rights reserved.