All room air conditioners function pretty much the same, although energy savings and cooling capacity vary by brand and model.

Like central air conditioners, room air conditioners extract heat and moisture from the room air, cool and dehumidify it, and then return the air to the room.

The basic components are a compressor, evaporator coil, refrigerant-filled tubing, and condenser coil. Coolant, or refrigerant, is pumped through the tubing between the coils to transfer heat.

The evaporator coil cools the indoor air. The condenser coil expels hot air outdoors. Fans move cool air inside the room and exhaust heat outside.