Author Topic: Air Con use.  (Read 1609 times)

VicW

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Air Con use.
« on: June 09, 2022, 02:42:55 PM »
There was a so called motoring expert on TV this morning discussing how to save fuel. His suggestion was that you should turn the AC off and thereby save 25% fuel. What a load of crap. I never turn my AC off and it possibly reduces my fuel consumption by one or two mpg but I have the benefits of AC all the year round. No mention was made of the damage you can do to your AC by not having it on, ie, drying out the seals etc, and causing gas leaks. Naga, the presenter, suggested you should drive with the windows open ignoring the fact that that is noisy and disturbs the air flow over the car thereby increasing the fuel consumption.

Vic.

John Ratsey

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Re: Air Con use.
« Reply #1 on: June 09, 2022, 04:58:33 PM »
I use the A/C when I consider it appropriate. This article https://www.bbc.co.uk/news/business-61745697 discusses the same issues as were mentioned this morning. I'm surprised it's taken this long to suggest to drivers that they drive more economically although, with the fuel price hike, people might try to heed the advice. Honda should re-publicise the Mk 3 Jazz getting from Land's End to John o'Groats without refuelling.
2022 HR-V Elegance, previously 2020 Jazz Crosstar

peteo48

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Re: Air Con use.
« Reply #2 on: June 09, 2022, 05:27:29 PM »
I'm no expert but they used to bandy about a 10% figure for air con. Not that difficult to believe because, on older cars, if you had the car on tick over then turned on the aircon the rpm would drop noticeably as the system drew power to run it

Modern A/C systems are designed to be much more efficient and climate control even more so as it will "turn off" the A/C when not needed. There is, as Vic says, the issue of the system failing if not used regularly.

I will, very occasionally, turn the A/C off if the conditions allow, ie no rain, reasonably warm but not too hot outside. I don't know why I bother though. I might be saving 1 or 2 mpg at best.

ColinB

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Re: Air Con use.
« Reply #3 on: June 09, 2022, 06:08:42 PM »
When I first got a car with A/C a couple of vehicles ago, I recall being quite worried about the effect on fuel usage. So I recall doing some checks on MPG with both A/C running and not running. There was no discernible difference. Logically, there must be an effect because the A/C must be using some power from the engine, but in practice it's undetectable and probably masked by all the other variables.

Not mentioned in the BBC item is the obvious one: get rid of the SUV!

Jocko

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Re: Air Con use.
« Reply #4 on: June 09, 2022, 07:19:19 PM »
I watched the same guy, from Drive Smart. When I got my car with AC I did the same test and found that the difference in mpg between on and off got lost in the noise, it was so insignificant. I ran that car for nine and a half years with the AC on all the time. In the winter it kept the interior dry and in the summer, cool. It even had a sunroof but I never opened it or slid back the blind.

Kremmen

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Re: Air Con use.
« Reply #5 on: June 10, 2022, 05:08:19 AM »
Same here.

As per my 3 previous Civics I've found the best option is aircon on auto and eco off. Then just turn the temperature dial as required.

There are lots of options regarding heating/cooling but I'd rather watch the road rather than adjust recirc, fan speed, vent selection, etc.

Honda aircon isn't as powerful, maybe for efficiency.
In my 2 Xantias and my IS200, I dialed up a temperature in summer and the aircon got very close to the temperature set. The air coming out was really icy cold and the fan speed kept on max for a lot longer.

In my 3 Civics if I dialled in the lowest setting then the interior only got down to ~24C and the fan speed reduced well before it should have done leaving the interior noticeably hot and stuffy, especially under a hot sun.

The temperature check was using an accurate digital thermometer that I've had for decades and placed in roughly the same car position to avoid sunlight and the vents.
« Last Edit: June 10, 2022, 05:22:35 AM by Kremmen »
Let's be careful out there !

guest9236

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Re: Air Con use.
« Reply #6 on: June 10, 2022, 10:58:38 AM »
Hi Vic
You mentioned NAGA. Sounds like a problem rather than a solution to air flow etc.

Bazzzer

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Re: Air Con use.
« Reply #7 on: June 10, 2022, 11:09:44 AM »
Use of Air Con is one of the factors mentioned on the BBC "Fact checker"-

https://www.bbc.co.uk/news/business-61745697

Kremmen

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Re: Air Con use.
« Reply #8 on: June 10, 2022, 11:36:18 AM »
Yes, that's what prompted the first post.

So called experts who think you should drive around in an oven when you've bought aircon.
Let's be careful out there !

Jazzdriver

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Re: Air Con use.
« Reply #9 on: June 10, 2022, 09:23:58 PM »
On a regular basis, a motoring journalist meets his requirement to submit a certain number of words by trotting out an article about saving petrol by removing roof racks, not carrying stuff in the boot and not using aircon etc  Just low quality journalism.  A European group of motoring journalists did a test that showed that figures that have been quoted for years were wrong and using aircon only has a very small effect on fuel consumption.  Of course, you should not carry junk in the boot if it serves no purpose.  But, as has been said, you've paid for aircon, so why not use it to cool the car when its warm and dehumidify it in winter?  It's a waste of money paying for aircon, but not using it.

Jocko

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Re: Air Con use.
« Reply #10 on: June 10, 2022, 10:05:33 PM »
On a regular basis, a motoring journalist meets his requirement to submit a certain number of words by trotting out an article about saving petrol
In all fairness the guy wasn't a journo. The guy was from IAM Road Smart I believe.

Lord Voltermore

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Re: Air Con use.
« Reply #11 on: June 11, 2022, 11:06:07 AM »
when I last looked ,back in the days when most cars had manual aircon (if any  ;)) the conclusion was the extra fuel needed for the aircon was about the same as the extra fuel needed to overcome the extra drag when the windows are open.

You could save fuel if the ambient weather allowed you to tolerate the windows being  shut without aircon. - 
Except they also recommended, and probably still do, that you use air con regularly, even in winter (when it helps dehumidify)  because  lack of use can make  refrigerant leaks more likely.

I think  climate control  means the aircon is self regulating. If cabin temperature remains close to your ideal setting setting anyway when the windows are closed it  will only use air-con  occasionally for short periods.   Opening windows would increase fuel consumption in most circumstances   plus  the noise and unwelcome insects, etc. 

With manual air con my wife preferred fresh air and birdsong  , except if in  a  city centre, or at high motorways speeds.  But she is much happier to have closed windows with climate control. 

  Trust a dog to guard your house  , but not your sandwich

Kremmen

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Re: Air Con use.
« Reply #12 on: June 11, 2022, 11:38:14 AM »
Reduces the need for regular vacuuming as well :)
Let's be careful out there !

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