Aircon fuel consumption increases - barchettaman
The link below *should* take you through AutoBild´s table of fuel consumption increases for 4 cars with their aircon on - a Panda, Zafira, C-class and a Golf.
The bit on the left shows the different ambient temps tested: 20, 28 and 33 degrees.
The middle bit gives a percentage fuel consumption increase at 50 km/h.
The bit on the right the relative increase at 100km/h.

snipurl.com/vium

Zafira registered a 25.8% increase at 50km/h...

Regards all,
Barchettaman
Aircon fuel consumption increases - Murphy The Cat
Thats one of the most imformative posts thats been made on here for quite a while (IMO)
The Zafiar certainly takes abttering doesn't it ? But the Merc gets awat with it quite well.

MTC
Aircon fuel consumption increases - Altea Ego
Probably becuase the Merc has more horsepower and is therefore less affected. That Zafira figure is certainly a shocker.
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TourVanMan TM < Ex RF >
Aircon fuel consumption increases - Bill Payer
Maybe the Zafira has extra strong a/c to cope with its glass area? I have a Merc C Class and the a/c struggles in very hot weather, so perhaps the compressor isn't particularly energy sapping.

The surprise to me is how little the Panda is affected.
Aircon fuel consumption increases - Number_Cruncher
If you look at the percentages, the Zafira doesn't come out too well.

But, I don't put percentages in the tank, I put litres in.

When you look at litres, it's the VW that takes the drubbing!

Number_Cruncher
Aircon fuel consumption increases - Murphy The Cat
When you look at litres, it's the VW that takes the
drubbing!
Number_Cruncher



at 28 & 33 degrees yes, but at the more GB friendly 20deg, the only one that would cause me any real concern is the Zafira - especially if I was doing a shed load of 30 mph work !

MTC
Aircon fuel consumption increases - Number_Cruncher
Mmmm - fair enough MTC, but I think that when you consider the smaller glass area, and smaller volume of air in the VW which must be cooled, I don't think the Zafira comes out of the comparison as badly.

I think that the test method might also be a little dubious. If, for example, via a quirk of the car's gearing, one car was revving harder than the other at a given road speed, there will be more energy wasted in the aircon - especially if it has a fixed displacement compressor.

Number_Cruncher
Aircon fuel consumption increases - Walton2
My father-in-law has an Omega with instant fuel read out on the computer. I don't know how accurate it is for exact mpg but it seems to react well to changes. E.g. Maintaining speed (ie raising revs) from the flat to a hill on the motorway produces a change in a few seconds of a few mpg. Switching the dual-zone climate control on and off produces a change of less than 1 mpg. Not a scientific study but it hardly seems worth sweating for that saving.
Aircon fuel consumption increases - Bill Payer
Switching the dual-zone climate control on and off produces a change of less than 1 mpg.


My C Class is the same - it's an average indication in that, but I can have balanced on cruise on the motorway such that a short hill drops it .1 or .2 and a down hill stretch puts it back up again. Switching the a/c on and off seems to make mno difference at all (except that the interior goes cold!).
Aircon fuel consumption increases - colinh
Just checked my brim-to-brim records for a Golf 2.0 TDI DSG used in Spain. September to May 5.78 l/100km (48.9 mpg) - Jun to August 5.86 l/100km (48.2 mpg) = 1.45% increase (decrease).

Would be interesting to see corresponding tests for driving with windows/sunroofs open v closed - steel wheels v alloy wheels - clean v dirty cars
Aircon fuel consumption increases - Peter D
Anyone figured out what the requested internal temp was. If it was 20 degrees then the aircon should hardly be working with a 20 external temp or was this done at max cooling/min temp. Regards Peter
Aircon fuel consumption increases - barchettaman
Internal temperature was set at 20 degrees.
Aircon fuel consumption increases - school boy
On the older veriaty of Saabs you could select economy mode on the aircon but I dont know if it made that much difference. It seemed to just work at half fan speed.
Aircon fuel consumption increases - Pugugly {P}
Makes on heck of a difference on the hybrid Hondas we have in work. Business Manager was the switches disabled !




Aircon fuel consumption increases - Pugugly {P}
Makes on heck of a difference on the hybrid Hondas we have in work. Business Manager was the switches disabled !





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735310 - Total sense in an upside down world.
Aircon fuel consumption increases - Pugugly {P}
eh ? - how did that happen ?
Aircon fuel consumption increases - Zippy123
About time aircon was used in official mpg figures then.
Aircon fuel consumption increases - tyro
Interesting link.

I notice that, in terms of percentage increase in fuel consumption, aircon makes more difference at low speed than at high speed. I presume that this is because more fuel is being used at high speed, and so, in percentage terms, aircon has less impact.

In the case of the Panda, however, it doesn't seem to make much difference. Why might this be?
Aircon fuel consumption increases - Big John
What I don?t understand is the big difference between consumption at different temperatures. I was always under the impression that climate control always ran the compressor but then mixed hot/chilled air to achieve the required interior temperature, only cutting out when the chilled air temp dropped to 5deg. I know most of these just have ?aircon? but it will be always "on" during all the tests.

P.S. Switching my Skoda Superb between ?auto? and ?econ?(compressor off) seems to make very little difference on the continuous MPG readout.
 

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