How does an air conditioner work simple explanation. An air conditioner works by removing heat from a room and releasing it outside. This is done by circulating a refrigerant through a closed system of coils. Steps Compress: The refrigerant gas is compressed, which increases its temperature and pressure. Condense: The refrigerant gas is sent to the condenser coil, where it changes into a liquid. Evaporate: The liquid refrigerant is sent back inside and enters the evaporator coil. Absorb heat: A