A direct evaporative cooler and a counter-flow cooling tower were simulated by the effectiveness–NTU method. One-dimensional energy and mass balance as well as heat and mass transfer equations were applied. The resulting algebraic equations were solved numerically. To validate the simulation model, numerical results of the evaporative cooler and cooling tower were compared with available experimental data. This simple application of the effectiveness–NTU method to such important heat transfer devices may prove pedagogically useful to undergraduate mechanical engineering students attending heat transfer courses.