What is the difference between a portable air conditioner and an air cooler?

• An evaporative air cooler uses water and an internal fan to naturally lower the temperature of the air blowing out, which works best in hot, dry conditions. A portable air conditioner (like our Bennett Read 9000BTU model) uses a compressor, refrigerant gas, and an exhaust hose to actively pull heat out of the room. Portable AC units offer far superior cooling power and work perfectly in humid climates, though they require a window to vent out the hot air.