The desiccant wheel is a key component in solid-desiccant systems that can be used in non-conventional building air conditioning systems in order to use renewable energy sources and also to achieve important energy savings. At present, the analysis of the behaviour of air handling units based on desiccant wheels is a complex task to be done by a design engineer. It is difficult to access a simple model that can represent the behaviour of commercialized desiccant wheels with enough accuracy. In this work, experimental results published in the literature of the global behaviour of desiccant wheels for different inlet states of the process and regeneration airflows and for different rotation speeds are used to investigate a new pair of independent effectiveness parameters and to derive correlations for their estimation. Tests of application of the easy and quick predicting effectiveness method are performed. A reasonable agreement with the experimental data is achieved. (C) 2011 Elsevier Ltd. All rights reserved.