Air Con - is it standard on a GTi?

[stealthwolf]

I found my return journey mpg dropped from 34-35mpg to 30mpg, which backs Greeners' statement of 10%.

[homesqueeze]

I thought i read somewhere that the air con is clever enough to self lubricate when its not being used, therefore you dont need to turn it on occasionally. Could be wrong though 

Unfortunately air-con is not intelligent, it would be good if it was though. One of the main causes of air-con failure is when it is off all winter and then turned on again when it gets hot. Personally I just leave it on all the time, its useful all year round.

You do realise it increases fuel consumption by around 10%? Plus it makes the air in the car very dry during a long drive.

Really I actually find the difference in difference in fuel consumption so negligable that it's not a worry for me. The aerodynamic drag of having windows open causes similar mpg loss as air-con. I don't find dryness a problem unless i'm on a super long drive and then I might cycle it on and off periodically.

How do you measure the difference if you have it on all the time? 

I've obviously experimented between having it on and off over time and like I said I do turn it off now and then on long journeys. The difference is only ever  2 maybe 3 mpg and when I can get up to 45 mpg with the air-con on, the difference is not much of a concern!