# Air Conditioning - How much extra petrol does it use ? ?



## allthedoyles (1 Jun 2009)

I know air-conditioning uses  more petrol , than normal driving.......I could nearly see the needle moving down , as I drove the last few warm days .

Anyone know how much extra petrol is been consumed , while driving with the A/C on.

Would the car use less fuel , if the fan setting is set to 2 rather than maximum 4 , while using the aircon.?


----------



## Frank (1 Jun 2009)

The fan makes little differnce the extra fuel is usd by the aircon compressor putting extra load on the engine.

If you switcch on the and off the ac switch you will hear the engine load up regardless of the fan. 

In my diesel passat it seemed to make very little difference wheter the climate control was on or off. 

Although I think climate tends to turn off the aircon pump when it is not needed so makes it a bit more efficient.


----------



## Bubbly Scot (1 Jun 2009)

I was regretting using the air con for a bit over the weekend when I found myself driving round the back roads of Cork trying to find a petrol station. The little light was on and I was so sure I was going to run out, Mr Bubbly was on his way to me with a can.

Was wondering those exact same questions myself, I don't use the air con usually but a three hour drive in this heat wasn't an option. I put it on for a few mins at a time.


----------



## mathepac (1 Jun 2009)

Frank said:


> ... In my diesel passat it seemed to make very little difference wheter the climate control was on or off...


This would be true of VW, Audi, Skoda, etc diesels. I'm not so sure about the petrol jobbies though.


----------



## gipimann (2 Jun 2009)

My car has a fuel usage meter, giving figures in litres per 100km.

I have noticed that my average usage on a motorway is about 6.5l / 100km.
When I switch on the A/C (fan setting 2), the usage increases to between 13 and 14 l / 100km.


----------



## leex (2 Jun 2009)

gipimann said:


> My car has a fuel usage meter, giving figures in litres per 100km.
> 
> I have noticed that my average usage on a motorway is about 6.5l / 100km.
> When I switch on the A/C (fan setting 2), the usage increases to between 13 and 14 l / 100km.



Double?

I read somewhere before that it increases fuel consumption by typically 10%.


----------



## gipimann (2 Jun 2009)

I don't leave the A/C on for very long, so perhaps the figures might come down, but that's what I see when I switch it on!


----------



## allthedoyles (2 Jun 2009)

Even without a meter , we would reckon fuel consumption did nearly double , during the use of air-conditioning .

Petrol engines , seem to use a lot more than diesel engines


----------



## woodbine (2 Jun 2009)

Also,  if it's too warm and you open some windows instead of using aircon this will increase "drag", thereby increasing fuel consumption also. 

personally i prefer the aircon if it's very hot and it happens so rarely that i don't mind the extra bit of fuel used. 

there are just so many factors that effect the fuel efficiency: load,  air pressure in tyres, roof racks. etc etc. It's hard to get it right!


----------



## Mini3277 (2 Jun 2009)

Air con is meant to increase consumption by about 10% whereas opening a window is meant to increase comsumption by about 15%. 

It's all a load of **** if you ask me. Put your foot through the floor for 5 minutes and you'll do much more damage to the fuel tank than pressing a button to turn the air con on!


----------



## daithi28 (8 Jun 2009)

It's also a false economy to never use your aircon btw.

The refrigerant in the aircon system also contains lubricant for the aircon pipes fitted in the car. If you never switch on the aircon, the lubricant does not lubricate the pipes and over time this can lead to cracking of the pipes and a loss of the aircon gas.

Result, you'll need new pipes fitted and the aircon re-gassed which will be more expensive than about about 2 years of occasional aircon use!


----------



## Ancutza (9 Jun 2009)

Really can't see any difference in my fuel consumption in my diesel powered car now that the aircon is on almost all the time as the summer temp rises.

The only time I notice the fuel consumption increase is when I (to quote Frank I think) 'drive it like its stolen'. Nice expression that.   But rest assured that rarely, rarely happens.


----------



## AlbacoreA (10 Jun 2009)

You probably don't notice the drop in power with a torquey diesel. With some petrol motors the drop is noticeable when it kicks in. 

As for not using AC not being an option. Of course it is. Its a nice to have not a need to have.


----------

