The portable air conditioner uses a process called evaporation, which lets it work more effectively than the traditional AC units can. It has a tank inside that you will fill with water(ices) and a filter. When you run the machine, it will pull warm air in through the back and send it through the filter. That air will mix with the water inside, which cools it down before it exits the appliance. It can run for up to eight hours without the filter freezing or the water inside getting too hot. It does three separate things; cooling, purifying and humidifying.