Air Con and fuel consumption

[sharkey]

Not wanting to sound like a skinflint but you always hear that using your aircon pushes up petrol consumption. Does anyone have any advice at all on this issue.

From one sweaty man. (and his Golden Retriver - occasionally).

[ctrlaltdelboy]

'tis true - you make your choice, spend or sweat ;)

[Kevin]

I spend, in more ways than one.

It's going to cost over £1000 to get the aircon fixed, and that's doing it cheap.

[Minch]

I think it might be worth the extra £1k to get it fixed considering how hot its been the past few days! Saying that the system does weigh a lot . . . hmmm . . . decisions, decisions!

[Papalazarou]

Not wanting to sound like a skinflint but you always hear that using your aircon pushes up petrol consumption. Does anyone have any advice at all on this issue.

From one sweaty man. (and his Golden Retriver - occasionally).

If you don't use the aircon regularly, the seals can dry out and the evaporator is more prone to bacterial infection (and I'm not talking clymidia)!

Pollen, nicotine industrial, pollution etc.. flow into the cabin, pass into the evaporator box and gets caught in water droplets which turn into bacterial growth which makes your aircon smell bad and can give you heyfever like symptoms; runny nose/eyes, sore throat etc...

Using you air-con all year round will reduce these effects.


James.

[Accelera Comigo]

I've heard the fuel consumption thing before and I don't buy it. OK there will be drag on the engine at the compressor pulley and the energy to overcome it can only come from one place but I've never noticed a drop in mpg in the NSX or any other car when the aircon is on, or summer to winter.

It is definitely true that you need to run the aircon every 2-4 weeks to lube the seals though.

Accelera Comigo

[Papalazarou]

There is a drain but I'm not sure how much it is. If you idle the car then switch on the air-con, the engine becomes more laboured.


James.

[AR]

Anecdotal data tells me that it does use more fuel. At tickover is already a couple of hundred rpm up so it is bound to use some more. :evil: No NSX at the moment, but on the Amazon the AC does use a lot more fuel and as an aside the Auto one uses even more fuel.

Cheers

AR

[million miles]

I have run a lot of cars with air con and climate controll ( the same thing realy) and although in theory they use more fuel the extra drag caused by having a window open adds up to the same thing.

dont have an NSX yet...................

[DTA-Motorsport]

Many years ago I did some research into the effects of running the AC or opening windows on fuel consumption - was a bit of a sad git at the time but i'm happy to report I've outgrown that phase :?

IIRC running the AC will cause an increase of between 1% and 2.5% in fuel consumption whereas opening the windows can add as much as 12%~15% to your fuel consumption :shock: Mind, this was taken from data back in 1995 from Chevrolet (I was living in Washington DC at the time) and modern engines may be more efficient these days.

In all fairness, I'm not overly concerned with fuel consumption. I don't own an NSX (anymore) and my 300ZX has a serious "drinking" problem. Having said that I do tend to get between 25 and 33mpg out of the old girl and that's with the AC on and driving the car like it was meant to be driven. Oh, and my autobox is currently acting up which, aside from causing me no end of headaches is also negatively affecting the car's fuel consumption. I would personally never buy another car without AC - it's such a blessing to have (not just on hot days either ...)

Dan

[Kevin]

On 'Mythbusters' (6pm Discovery channel, excellent prog) they tested whether aircon uses more fuel than opening windows.

They concluded that under 50mph opening windows is better, over 50 and its better to use the aircon.

This was in an American tank of an SUV though, results would be different for various shaped cars.

[AR]

That is why when it is hot I use the AC, and sometimes I just use the fan, with the windows up.

Cheers

AR