air con

[brian j john]

trying to find out accurately how much would the air con in my car (1.8 vectra petrol ) costs per year if it was left on all the time and say putting �25 of petrol per week

[Buenchico]

The effect of air conditioning upon fuel consumption varies greatly depending upon the type of driving (with city driving costing more than open road driving) and the ambient temperature.

Most source estimate that the use of air conditioning adds between 10% and 20% to your fuel bill. So a (very) rough answer to your question would be around �200.

Chris

[brian j john]

thank you chris , i fully understand about the type of driving and that's probably why it would be very difficult to be accurate about it but i've had several estimates of between 1% to 20% but thanks again for your contribution


BJJ

[Buenchico]

. . . and thank you for your reply.

This link might be of interest:
http://www.northlan.gov.uk/business+and+employ ment/roads+and+transport/smartways/what+driver s+should+know.html

Chris

[Panic Button]

If you try to save fuel by leaving the A/C off and opening windows you will fail.

Opening windows increases drag and increases fuel consumption.

[Lastmanjack]

On average its about 20%, Automatic air con works best & if you set it at 22 instead of 18 it will cut in less often, but you dont have to use it at all, so fry or chill out its up to you,
as with all mod cons there is a price to pay, everything you switch on in a car causes more strain on the engine & more use of fuel, even the radio.

[markysngc]

theres a good viewpoint on this here

http://www.airconditioningforcars.co.uk/ACpage 05.htm

[Zax47]

A recent test on Mythbusters on the Discovery channel, into the fuel consumption effects of opening windows vs using aircon, had interesting results.

Up to 45mph then opening windows had LESS effect on consumption than aircon, but above 45mph then the opposite was true as the drag effect kicked in. Of course, turning the aircon off and keeping the windows shut has the least effect on consumption.