Portable air conditioners work by pulling warm air and moisture out from the air and cooling it. Many portable air conditioner units work with self-evaporative technology. This means the moisture from the air is collected and processed internally, before being expelled via the exhaust. In some regions, where humidity is a problem, there could be an excess of water needs to drain somewhere. It can either be collected in a tank or tray within the unit, or it could be expelled via a hose.\r