Heavy duty air cooler produces effective cooling by natural process. The air cooler is designed in such a way that the water is spread on the media or cellulose pad and fresh out side air filtered through the saturated media is cooled by evaporation and circulated by a suitable size blower. The air cooler maintains 28 degree c -35 degree c inside when outer temperature is 40 degree -45 degree c with minimum humidity. Heavy duty air cooler ensures optimum functionality for longer period of time.