If your project is connected to a district cooling system and you want to show that a CFC phase-out is not economically feasible, engage a qualified, independent third party to prepare an analysis demonstrating that both conversion and replacement will have a net ten-year cost. This is determined by a simple payback calculation that subtracts the ten-year cost savings (from energy and maintenance savings) from the cost of the system replacement or conversion. If the number is zero or negative, this represents a cost after the ten-year period and the system will be considered not economically feasible.