Evaporative air cooling is the natural way of cooling, similar to a breeze flowing across a lake. This breeze lowers the temperature and has a relaxing cooling effect on people. An evaporative air cooler cools the air by means of the evaporation of water. When water evaporates into the air, the result is a mixture of air and water molecules. This chemical change requires heat, thus energy or latent heat is taken from the air molecules – dropping the actual temperature of the air. The recommended maximum humidity level is 60% or less, to allow a noticeable temperature decrease* and helps people to feel more comfortable. The temperature decrease* will be larger in dryer climates because the lower the humidity, the more evaporation occurs. When used for cooling, the evaporative air cooler should not be used in enclosed spaces. It must be kept level and there must be water in the water tank. The room should have doors and windows opened to allow free air flow. An evaporative air cooler works best when placed near an open window. Fresh air is drawn into the cooler, circulates in the room and exits via the door. The maximum cooling effect is felt when a person is in the flow of air coming out of the evaporative air cooler.