What is an air-conditioner?

An air conditioner is any type of device that helps moderate temperature indoors. An air conditioner does not have to be a cooling system, technically a heater is also an air conditioner, though most people seem to only consider air conditioners (sometimes referred to as A/C units) machines that lower the temperature to a user defined temperature.

An air conditioner is a machine that filters/ventilates out hot air and cools the inside of a room or building. Air conditioners come in many varieties, ranging from wall-mounted units to portable units.