The evaporative humidifier is an energy efficient unit that can be an alternative to other costly cooling systems; depending on climate conditions and building load characteristics. Heat and mass transfer processes occur inside the humidifier as a result of air contact with water spray. The present experimental study aims at investigating some common parameters that have a direct or indirect effect on the evaporative humidifier performance. Among these parameters are: the number of spray nozzles, nozzle arrangements, water-air mass flow rate ratio, and packing material specifications such as: location, z, thickness t, and number of trays. The results showed that the water-air mass flow rate ratio has a significant effect on the humidifier performance. The results also indicated that an increase in the humidifier saturation efficiency, ε, was noticed as the number of spray nozzles increased for the same water flow rate. However, when keeping the water spray supply pressure constant, a decrease in the saturation efficiency was recorded as the number of spray nozzles increased. Furthermore, placing a packing material inside the humidifier results in enhancing the efficiency due to increasing the mass transfer surface area and air residence time.