On 12 Aug 2009 21:52:43 GMT, "Michael R N Dolbear"
wrote:

Note that train energy figures include Air Conditioning, the standard
car figures exclude it.


Air conditioning is an interesting topic. It does use a small
additional amount of fuel, but in a car, that additional amount is
smaller than would be caused by the increased drag when the windows
are opened.

So given the choice - opening the windows or switching on the aircon -
there is no doubt that the aircon is more environmentally friendly
than opening the car windows*.


*Cue some idiot trainspotter suggesting that opening car windows
should be banned.