Air conditioners are appliances designed to cool and dehumidify indoor air for improved comfort. They work by extracting heat from the air inside a room and transferring it outside, using a refrigeration cycle. Air conditioners come in various types, including window units, split systems, portable units, and central air conditioning systems. They are used in homes, offices, and commercial buildings to maintain a comfortable temperature and humidity level, especially during hot weather. Modern air conditioners often include features such as programmable thermostats, energy-saving modes, and air purifiers for enhanced comfort and air quality.