As we approach the ten-year anniversary of the chlorofl uorocarbon(CFC) ban that took effect in 1996, only 57% of the estimated85,486 large tonnage CFC chillers in the U.S. and Canada have beenreplaced or converted. According to the estimates from the Air-Conditioningand Refrigeration Institute (ARI)1 and the Heating, Refrigerationand Air-Conditioning Institute of Canada (HRAI),2 by the end of 2004,approximately 37,000 CFC chillers still operated in North America.