Tom Heap investigates those businesses and organisations that over-use air conditioning, and in doing so make a significant contribution to global warming. It is a little-known fact that the gases used in air conditioning and chiller cabinets are between two and three thousand times more potent in terms of global warming than CO2. And yet air conditioning is becoming more commonplace in modern buildings and the home. The other major source of these harmful HFC gas emissions in Britain is supermarket chiller cabinets. Some supermarkets are making efforts to switch to natural 'green freeze' refrigerants, though others are reluctant to act.