Aircon or open window? Fuel cost

mistyarthur

It may not use much more fuel but thinking about it go out and sit in your car on a cold morning and turn on the a/c with the fans on full and you will see the rev counter going up just slightly, but the amount it goes up would indicate that there is very little fuel used I suppose.

zappahey

mistyarthur wrote:

It may not use much more fuel but thinking about it go out and sit in your car on a cold morning and turn on the a/c with the fans on full and you will see the rev counter going up just slightly, but the amount it goes up would indicate that there is very little fuel used I suppose.

There's no correlation between how much the tacho changes and the extra fuel used. It's the fact that extra fuel is required even to maintain the same revs because of the load imposed by the a/c compressor.

zappahey

Lob_Rockster wrote:

my car has a uprated battery so in theory the extra power needed is provided by that battery. Plus with automatic climate control, it does not blow hard all the time ergo the battery can recharge efficiently.

As already pointed out, the battery does not run the a/c it is driven by the engine through a belt.

In addition, if something is being driven from the battery, where do you think the power comes from that recharges the battery? The voltage pixies?

Wig

moonrakerz wrote:

On a recent edition of "Mythbusters" they came to the conclusion that up to 50/60 mph you were better off with the windows open, above that speed the increased drag was more than the increased consumption used by the A/C.

This would depend on the extent to which the windows were open. If I'm hot and going over 60 the first thing I'll try is to put the fan on, if that's no good I'll open my window no more than halfway. Opening all the windows fully would just be stupid - except at low speeds.

Lob_Rockster

zappahey wrote:

As already pointed out, the battery does not run the a/c it is driven by the engine through a belt.

In addition, if something is being driven from the battery, where do you think the power comes from that recharges the battery? The voltage pixies?

from the continuum transfunctioner?

tomstickland

The flux capacitor.

michaels

I can't understand how anyone could have a car without a/c - unless getting out of a car as soon as the outside temp goe sover about 20 degrees looking crumpled and smelling worse is not an issue...

Or may be it is only in the South East that you can be sure that every journey will involve long periods moving slowly and on the motorway the drone from having a window open any amount is unpleasant and distracting - plus of course wherever you are you are fully exposed to all the pollutants and hay fever inducing pollen with the window open rather than the filters having a go at cleaning it first.

boatman

Theres quite a bit of info in these articles.

http://money.cnn.edmunds.com/ownership/driving/articles/106842/article.html
We Test the Tips

http://www.fsec.ucf.edu/Pubs/energynotes/en-19.htm
Energy Efficient Transportation for Florida (FSEC-EN-19)

tomstickland

michaels wrote:

I can't understand how anyone could have a car without a/c - unless getting out of a car as soon as the outside temp goe sover about 20 degrees looking crumpled and smelling worse is not an issue...

Or may be it is only in the South East that you can be sure that every journey will involve long periods moving slowly and on the motorway the drone from having a window open any amount is unpleasant and distracting - plus of course wherever you are you are fully exposed to all the pollutants and hay fever inducing pollen with the window open rather than the filters having a go at cleaning it first.

I just drive around with the window open. Doesn't bother me.

stickytoffeepudding

...fuel consumption increases if you put those daft flags on your car! Apparently flying them during this years world cup is going to cost an extra £4m in fuel costs in the UK!!! Don't know where it came from, but it sounds truly scary!!!
Of course MSE's have more taste than that...:rotfl: