Effect of A/C on MPG
 

I have always tended to keep the A/C on auto, partly out of habit, and partly because cool air helps keep me awake on long journeys. However, I would be interested to know how much difference it makes to mpg to have the A/C on Econ rather than Auto.

Always believed the effect on mpg was negligible, it's not that much of a strain to drive an air con pump/compressor. I've no figures but await further replies.

Cheaper than driving with your windows down and ruining the aerodynamics! ;)

Although I run Ed's ATC 24/7 365, pretty sure they did this Mythbusters a few years ago and below 40 mph, turning off the air con and opening the windows was more economical and above 40 mpg, closing the windows and running the air con was better? :shrug:

I couldn't get a difference of even 1mpg on the fuel computer when I tried to test it using the same regular run.

Not sure what that proves - not much really.

Well the difference is letting wasps in or being cool 😀

This might be of interest......

http://www.autoexpress.co.uk/car-new...pg-mythbusters ;)

The way Look at it is that hot summer days appear now to be far and few between but when it is hot and I am on a short or long journey I like to travel in comfort with the air con blasting aware. Forget the expense (which would be minimal anyway) and live the dream.
Alternativley in a winter when it is cold I like nothing better than warming the car up for a short time and plonking my rear end into a nice warm, heated seat.... Bliss. :driving:

I agree; whilst I appreciate the fuel economy of my car, a large part of my reason for buying it was the comfort it affords during long journeys. It would be a shame to become so preoccupied with frugality that the luxury of our cars is not fully enjoyed.

It proves that, if there is a difference, it's too small to measure and therefore insignificant.

Simon