HCFCs are used extensively in the refrigeration and air conditioning industry, in particular in the airconditioning industry. Parties to the Montreal Protocol, in their 21st meeting, adopted a decision concerning HCFCs and environmentally sound alternatives. The decision calls for further assessment and support work to enable parties to find the best ways of moving forward particularly for those with forthcoming compliance targets related to consumption of HCFC in the air-conditioning sector. The aim of this program was to individually test custom-built AC split unit prototypes and central unit prototypes, to operate with alternative refrigerants and compare their performance against baseline units. Those baseline units are either HCFC-22 or R-410A.