Hi all,
I remember seeing a while back an article about different car models and the effect air conditioning had on the overall MPG of a car, but cant seem to find it.
Does anyone happen to know if anywhere does such research? If not, if your using air conditioning yourself, what effects do you see to your car's economy?
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approx 7%
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Golf 2.0 TDI DSG - auto climate control - Spain - assume a/c use Jun-Sep, rest of the year economy setting, i.e., cooling/heating as necessary but no a/c
From brim-to-brim records over two years - Jun to Sep 5.66 l/100km (49.9 mpg) - Oct to May - 5.61 l/100km (50.4 mpg) = 1% difference
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on my 2.0 tdi A4 I find that using aircon drops my mpg from 48 mpg to about 43 mpg on a motorway cruise.
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Hard to tell as it's not on all the time, especially as mine is climate control rather than straight AC.
Going from trip readings I believe mine drops from about 50 motorway to about 48 with it on a lot of the time. Non motorway too many other factors to tell with any consistency
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Hard to tell as it's not on all the time especially as mine is climate control rather than straight AC.
>>Isn't Climate control A/C with a thermostat??
MD
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>>Isn't Climate control A/C with a thermostat??
yes which means the compressor isn't running as much.
At least it does for me I just reckon, compared to the last car I had with AC about 7 years ago, that it's on less.
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About the same effect as having the lights on most of the time in the winter...
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Interesting results. I often leave it on for about 10minutes or so then turn it off until needed again, so I doubt that has much effect on the economy of a HDi 110 at all.
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I never used to notice on my Passat B5.5, but I wasn't being scientific in recording the figures either.
It didn't have a noticeable impact on MPG figures either way ... I think unless you have it blowing at full tilt cold it probably doesn't absorb that much power anyway.
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Does it follow that the larger the engine, the smaller the effect?
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I remember the article, the difference between models was huge, and it didn't seem to be that larger engines took less of a penalty, it seemed random, I suspect the test was flawed myself, as they didn't run multiple tests to see what the range of results were (margin of error)
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Was it a german article? I really have tried looking, cant seem to get it up.
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Was it a German article? I really have tried looking cant seem to get it up.
Talk to your Doctor!...She may be most helpful!
MD
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LOL! Up ... on google , sorry to say :-)
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>>Does it follow that the larger the engine, the smaller the effect?
No, that's the sort of twaddle you'll hear from motoring journalists! (even ones with hats!)
There's no connection or link between engine size and the heat load that the aircon must work against, or the sizing and efficiency of the air conditioning system.
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On my diesel, I've never found the a/c to make much of a difference in mpg overall.
However, when it is very hot outdoors and I have the a/c on, when pulling away quickly I need to put a lot more 'gas' otherwise the engine can threaten to stall. I suppose all cars must have variable displacement compressors otherwise they wouldn't be efficient in the cooler months.
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I have to confess that with my Panda 4x4, heavy car, small engine, I sometimes need to switch off the aircon to produce enough oomph to overtake and get up some steep hills.
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The Mondeo used to return about 4 mpg less (just under 10%) when the air-con was used, but you could really feel it knock the stuffing out of the performance when the compressor cut in - on a car where performance was marginal anyway, I'm not surprised it made such a difference.
This refill will be interesting on the Volvo as I've used the air-con extensively this week. I must admit, it's the first car I've owned where the system makes no perceptible difference to the performance - economy though, is TBC.
Cheers
DP
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I have to confess that with my Panda 4x4 heavy car small engine I sometimes need to switch off the aircon to produce enough oomph to overtake and get up some steep hills.
On some cars (maybe all?) the compressor disengages when the accellerator is floored.
I too remember that the article referred to showed large difference in with / without fuel consumptions - much greater than seemed the case in my experience.
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>> I have to confess that with my Panda 4x4 heavy car small engine I sometimes
need to switch off the aircon to produce enough oomph to overtake and get up some steep hills.>>
We particularly notice the effect in SWMBO's Focus 1.6 (petrol) when pulling away at roundabouts etc. It can catch you out ...... in fact, if we are driving in town, we normally resort to switching it off.
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In the 405 I had the engine could be heard to slow down and the performance blunted however with the C5 you can't tell - maybe because of the variable compressor?
It's worth a few mpg to drive in comfort, just being a bit easier on the pedal would probably make up the difference.
Steve.
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I've done brim to brim tests on my 2.0tdi Jetta sport with the AC on and off and it makes no perceptable difference.
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It depends where you live and the average differential temperation from outside ambient and what you have selected inside the car. I live is Scotland and rarely use Climate Control other then to excerise the system. It was on yesterday and I guess there was a 4 degree delta but it was not long enough to produce numbers. Regards Peter
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I´ve dug out my original post - I think it´s the one you are referring to - and ensuing discussion:
tinyurl.com/2vagt5
Enjoy.
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Never noticed a difference in mpg with my diesel B5.5 Passat, with climate control on. I could never actually tell when the airconditioning actually cycled off and on though. No dip in revs at idle.
Now- my Hyundai coupe also has climate control but the system does actual show, via indicator lamps and an LCD diagram, where it is distributing the air to and if the A/C is actually on. On the warmest days so far this year, with the thermostat at 22°C, it has only been on at the start of a journey. At idle the engine speed does actualy vary when the system kicks in. Not clever enough to provide demisting in cold wet weather though.
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