The major advantage of an evaporative cooler is its energy efficiency. Evaporative coolers use significantly less energy than traditional air conditioning systems, as they rely on the natural cooling process of evaporation to cool the air. This process requires only a fraction of the energy used by traditional air conditioning systems, resulting in lower energy bills. Additionally, evaporative coolers are more environmentally friendly than traditional air conditioning systems, as they do not use refrigerants that can harm the ozone layer.