Interesting Comparison

[dncm1]

Last week I filled up with petrol in London and drove up to my home near Newmarket. A journey of about 70 miles - about halve on the M11 and most of the rest on good quality A roads, with the last 5 miles or so on country lanes. After filling up, I zeroed the mpg meter and was rather amazed to see that I averaged an indicated 35.6 mpg for the trip. Then I realised that the climate control was switched off so no a/c on.

Today I did exactly the same journey, filled up at the same garage, and drove up under very similar conditions - except that I had the climate control (and a/c) on and the ambient temperature was about 5 deg C cooler. This time I averaged 32.0 mpg. Still not bad, but 10% worse than last week.

[lfoggy]

Interesting.

On warm days I like to switch the climate control off and have the windows and sunroof open but apparently that's even worse for fuel economy because of the increased drag.....

[ihpj]

Not sure how accurate that may actually be - until you do a proper 'brim-to-brim' test.

I know the OBC is fairly reliable, but it can mis-estimate sometimes ;)