How much does it cost to fill my car air conditioner with freon? Several factors come into play when determining price. First it must be determined how much freon, if any, is left in the system. If the system is just a little low and no leak can be found a small recharge may be all that is needed. If however the system is very low adding freon with large amount of air will not produce cold air. In these cases evacuating and recharging the system, while adding leak detection dye to find out how the freon escaped is in order. In all cases, thoroughly searching for the leak is a priority. Our technicians can get you back to driving comfortably in the summer heat.