Due to the ongoing rise in the global population, demand for energy continues to increase, which has led to global warming and climate change. The energy utilization by buildings needs to be optimized to minimize the amount of heat entering its defined space when it is being cooled. Air conditioning systems are used to mitigate this problem. However, they have many limitations and face many challenges, such as their high energy consumption, steep costs, and high levels of ozone-depleting pollutants. To overcome these challenges, a cost-effective and energy-efficient system is needed. This work aims to construct a rotary evaporative cooler unit with a focus on increasing humidity while reducing the temperature of a closed space. A rotary wheel frame is fabricated with a wire mesh and is fed with coconut coir, which is a material made from natural fiber. The wheel, which is half dipped in the unit’s water, is rotated by the unit’s motor. This experiment is carried out at various air velocities and various motor rotation speeds. Performance values, such as those measuring changes in humidity, temperature, efficiency, specific cooling capacity (SCC), the coefficient of performance (COP), and the rate of evaporation are determined. The results of this experiment indicate that the system yields a COP value of 1.84 and a humidification efficiency rate of 83%.