But this can be a false economy as the drag created by the open window can significantly affect their car's aerodynamics and therefore fuel consumption.
In warm weather an open window may be a better option for fuel saving motorists in stop-start traffic, but once moving freely on the open road, it's advisable to turn to the air conditioning.
It's also worth suggesting that while driving on the open road, once your car has cooled, to switch off the air conditioning and the incoming fresh air alone will probably keep you cool enough.
