Describes an effective method of desiccants matrix performance testing and a computer program that uses empirically derived performance algorithms to predict the performance of desiccant systems using the tested matrices. The testing method requires only a small sample of matrix to optimize the working parameters of the desiccant wheel used in dehumidification or desiccant cooling applications. During testing, a stationary matrix sample is exposed to multiple and reversing flows of process and regenerating air-streams. This simulates conditions to which the material is exposed in a rotating desiccant wheel. The main advantages of using this method, in comparison to a whole wheel or entire system testing, is an ease in manipulating optimising parameters (e.g., ratio of regeneration to process cycle), size (cost) of matrix needed for testing, and low volumes of air flows requiring conditioning and control during testing. The results of dynamic testing of matrix samples correlated well with manufacturers' data of desiccant wheel performance.KEYWORDS: year 1997, Testing, desiccants, performance, calculating, computer programs, algorithms, dehumidifying, air conditioning