An evaporative cooler HVAC system is a type of air conditioning system that uses the natural process of evaporation to cool air. It works by drawing in hot, dry air and passing it through a wet pad, which causes the air to become cooler and more humid. The cooled air is then circulated throughout the home or building. Evaporative coolers are an energy-efficient and cost-effective alternative to traditional air conditioning systems, as they use less energy and require less maintenance. They are also ideal for dry climates, as they add moisture to the air.