When your air cooler draws in warm air, it passes through a wet cooling medium. As the warm air passes through the medium, it gets mixed with the water that is in the cooling pad. This not only causes the water to evaporate but also makes it lose heat. Thereby, resulting in cooler and moisturized air. Next, a powerful fan of the air cooler sets the cool air into motion in the room. If it is an outdoor area then it does the job outdoors. Thereby, resulting in the circulation of old and stale air out of the room and allowing a constant flow of cool, fresh, and moisturized air.