A portable air cooler is an appliance that lowers room temperature by releasing water into hot air; it is also easy to move from room to room. A portable cooler may be easy to carry due to its small size and weight, or it may have wheels for mobility.
After water has been added and the unit is turned on, a fan blows the liquid into the air through absorbent pads, where it turns to vapor and drops the temperature. Because it uses the process of evaporation, an air cooler is also known as an evaporative cooler. Other terms for this appliance include desert cooler and swamp cooler.