Air conditioning is the biggest culprit in producing 'rogue' fuel consumption figures, upsetting running cost calculations. Data listed in the VCA booklet, New Car Fuel Consumption Figures, is calculated without air conditioning being turned on and gives no warning of the effect it will have. The AA wants car makers to provide information on the fuel costs of non-essential equipment like air conditioning, which it says can reduce fuel consumption by as much as 15%.
The SMMT dismisses the comments, saying there is an infinite number of factors which alter consumption compared to the figures achieved in test conditions. A spokesman said: 'The fuel consumption figures are there as a benchmark and will be used to create the basis for carbon dioxide-based company car tax in 2002. Any changes now would throw everything into confusion.'