Air Conditioning In The Car.

[Tilly2]

Why does the car use up the petrol more quickly if you have the air conditioning on?

I have to keep putting petrol in. It's not lasting any time at all.

[Graham-W]

You are asking the engine to drive an extra pump which works the air-con. This takes more energy and therefore uses more fuel.

[woofgang]

because its drawing power to run the compressor that makes the cold air.

[Tilly2]

Oh, I see, Graham. Thank you. Nice simple answer there.

[Tilly2]

Thank you too, woof.

[gness]

I think it's only at low speeds, Tilly....on modern cars it should be less noticeable at higher speeds....x

[heathfield]

Just like when you're driving with headlights on, when the alternator has to supply a higher amperage to compensate for the extra drain on the battery. This can reduce your MPG by around 1¼ to 1½%.

[Graham-W]

There's an ongoing argument about whether driving with a window wound down, causing extra turbulence, uses more fuel than running the air-con to cool the car.
I've never seen a definitive answer. Mythbusters did trials a couple of times without drawing a firm conclusion.

[Tilly2]

Gness, my car never goes faster than 30 mph, if I can help it. That's why I have to keep refueling, I think.

I don't like going fast.

[gness]

Hi, Graham....the report I read....don't know if it's right....said windows down when stationary....closed and aircon on when moving.....though it has to be aircon for me, but I'm usually driving....fairly quickly.....☺

[gness]

Made me smile.....just looked at AA eco-driving advice....one recommendation is....Lose Weight.....I really had to think for a moment.☺

[Graham-W]

Gness. There's a couple of interesting graphs halfway down this page if you can be bothered. I agree with you if it's very hot. Air-con makes me more comfortable than window down ( at any speed).
http://www.vox.com/2014/5/24/5745364/why-rolling-down-your-cars-windows-is-more-fuel-efficient-than-using

[Tilly2]

The part about ice vests is interesting. I could do with one of those on now.

[gness]

Thanks, Graham....did you notice one of their recommendations? Aircon off, windows closed and buy...for a few hundred dollars...an ice vest to stay cool whilst driving....and saving fuel......☺

[Graham-W]

LOL at "ice vest".

[Tilly2]

Can you get ice vests in the UK, I wonder?

[gness]

Tilly, large cool bag with three holes cut in it?

[Old_Geezer]

You get nothing for nothing, generally speaking. If you run a/c then it is powered from faster fuel use.

[Tilly2]

Large, gness? Don't be rude!

[gness]

Sorry....small cool bag........etc...☺

I'm happy to pay, OG....doesn't happen often.

[boxtops]

You can indeed, tilly, but very expensive (more expensive than petrol!) - not sure if the fit guy is part of the deal.....

http://www.getgeared.co.uk/rev_it_cooling_vest_liquid?utm_medium=shopping_feed_uk56&gclid=COPsiaWNz78CFYfJtAodlCEApw&utm_source=google