The gas is then propelled through a series of coils where it dissipates its heat and condenses into a liquid. Next, the Freon moves through an expansion valve where it becomes a cold, low-pressured gas. Then, the gas runs through another set of coils within the indoor unit that allows the gas to absorb heat and cool down the air inside your home. Fans placed near these coils help to propel hot air outside and move cool air inside.