Air conditioners are damaging the environment. One widely used coolant gas, HCFC, damages the ozone layer. With booming sales of domestic A/Cs around the world, the problem has grown in recent years, despite vigorous international efforts to reduce ozone depleting chemicals. Under the international agreement, known as the Montreal Protocol, HCFC will be phased out worldwide by 2030. An ozone-friendly replacement gas HFC – is now used in Europe but that gas is a potent greenhouse gas which means it contributes to global warming. However an answer may be at hand. Earth Report travels to China, centre of the global A/C industry, to investigate the cost of cool and meets the industry representatives working on a solution – and Sa DingDing, a musician with extreme views on air conditioners. With thanks to UNEP, UNDP, the World Bank, UNIDO, GTZ, IGSD.