I always drive around with the 'AUTO' option set, and let this set the temp accordingly. However, i have just got a new job and my annual mileage as a result will go up from 4k to 20k per year . So with trying to be a bit more concious with fuel consumption, if i take the auto setting off, can i expect better figures with consumption? My theory being that the AC won't be used a result but just the normal fan circulation. Or is this a flawed understanding? Ideally i appreciate a diesel would be the preferred option, but considering i have only had the car a few months- i'd loose too much selling and buying a diesel equivalent.