Air con and MPG !

[cardinalchunder]

I know that using the air con uses more fuel but just how much more?
If for instance I am getting 600 miles per tank, how many miles would I get if I used the air con for that whole 600miles?
CC.

[prolfe]

Air con can effect the MPG by as much as 5-10%

Over a year this can obviously add up. However you'd need to offset this against the cost of getting your air con re-charged as by not using it in the winter can mess it right up.

ask anyone who's bought a second hand car where the air con is rubbish. It's cos its previous owner only used it on hot days.

There is also an argument to say that having your windows open whilst travelling at speeds in excess of 30mph also is detrimental to mpg.

Golf clubs can effect it, roof box, tools etc etc

WhatCar's report on the use of air con and mpg:
http://www.whatcar.com/news-special-report.aspx?NA=217592&EL=3144038

quite an interesting article about aic con v windows open:

http://www.liveleak.com/view?i=b9e_1214963046

"As a result, its fuel economy was noticeably affected when the windows were rolled down at highway speeds; at around 68 miles per hour (the test's maximum), there was barely any difference between air conditioning and nature's cooling. If you were driving the sedan any faster than that, the increased drag would presumably make AC the more efficient option."

[tr8]

Its more when and were, i am a very high milage user, i will often do 500miles a day mostly motorway, in this case you cannot notice the economy if its on or off its the right foot that is more noticable.
On the rare days i go into london my economy drops like a brick, and i do notice the engine change for the air-con on / off.
Ie: I average 59mpg out of my 2.0tdi passat normally never less than 54mpg this is over the last 50k miles.
I had 1 month going into london spring time, even though still doing 120 miles a day so some motorway i strugled to get 44mpg

[hongkongstuey]

i havent noticed any change in my passat wether its on or off, get 600 miles per tank whatever, got 58mpg today on drive from derby to ironbridge, a38 - a5, national speed limit all the way, 5 adults in the car, luggage and air con on freezing cold, i'd say that if anyone was going to scrutinise there economy so much about wether to use air con or not, they shouldnt have it in the first place.

[cardinalchunder]

Thanks for your replies, looks like the air con will be on the whole way down to the south of France, especially if the weather is going to be anything like this weekend!
CC.

[prolfe]

I have mine on all the time, well, whenever the climate control thinks it should be on. I just set the temp and off it goes.

Where abouts in France are you going?