Simply put, freon is used to cool warm air. Freon itself is a chlorofluorocarbon (CFC) and because of this it is being phased out of use in air conditioners. It cools the air through the HVAC unit’s compressor and system of coil by compressing R-22 gas until it is hot; at which point it moves through coils to cool it down to liquid. When the liquid R-22 absorbs the warm air outside it pushes cold air out – repeating this cycle while the air conditioner is running.