Abstract: An evaporative humidification unit of modular construction readily adapted for assembly in selected configurations is provided. The configuration or array required for a particular installation is determined, and a supporting framework for the configuration is assembled from a selection of standardized structural components. The framework defines an array of compartments for basket or container units containing discrete, randomly-oriented flow-diffusing packing elements. The front and rear faces and floor of the basket units are mesh covered whereby air may be drawn transversely through the mass of diffusing elements while water is flowing downwardly therethrough. Spray units are positioned above the baskets for spraying water onto the mass of diffusing elements, and a collection pan is located beneath each basket for collecting and carrying away water which flows downwardly through the mass.