How can I use the air con in a way that won't reduce fuel economy?

I know that a/c reduces fuel economy, but what would achieve better fuel economy - to set a higher temperature and higher fan speed or to set a lower temperature and lower fan speed?

Asked on 9 July 2017 by DOMINIC ALLAN

Answered by Honest John
It barely has any effect at all on fuel economy on a long run. Opening the windows creates so much drag that the car will then use more fuel than running with the a/c on. However, in stop start traffic it will increase fuel consumption more than opening the windows.
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