Office debate: Air Con in a car = Less MPG

[binge]

Sometimes I wish I was back in the workshops! Working in an office means working with a bunch of biatches.

Having a little debate at work about Air-con on motors.
I drive an older Fiesta now, as I'm waiting for some dosh from the insurance, to buy another new motor. I stated earlier that I cant wait to get another car with Air-Con now summer is coming.

Few of the lads in the office, who drive nice new, shiney motors with air-con, are saying they hate using it, because it makes their cars use more fuel.


I totally disagree with this, Especially on modern cars.
Granted, the Air-con pump might draw a bit of energy from the engine, but what these office nerds cant get into their heads, is that putting your window down to keep cool, will cause the car to use a LOT more fuel than simply putting the air-con on.

I miss working with logically minded folk.

So turning to the highly opinionated minds of BCF to give their opinions on Air-Con.

Sorry it's a bit of a boring topic!




Ben

[dogbot]

Both winding down the window and putting on the air con will decrease your MPG... a little.

But I fucking hate car aircon. Recirculated gas, it's like breathing in something nasty, and it does my eyes in.

[binge]

[dogbot]

Errr... The whole system is a recirculated gas system...

Moot point anyway, my car doesn't have it, it's too old.

But I'd probably find another means of travel rather than taking a long distance journey with someone who insisted on using it.

[hellbound]

it does a little as stated.

but then so does driving around with a boot full of de-icer, scraper, change of clothes for the kids, blanket, half a beach that the kids pick up last summer and I have never got around to taking out, same with buckets and spades, two bags of charity shop clothes that haven't made it that far yet....the list goes on.

and then theres the extra weight in the door pockets and glove box and numeruos other stupid places.
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May you always see the road rising up to meet you and your enemies defeated in the mirror behind.

[binge]

Ah right, My Golf used to have Climate Control, but you could choose between Re-circulate and non-re-circulate.

Either way, I fucking love it!



Ben

[binge]

[UnknownStuntm...]

[J4mes]

The gas is sealed in a system and causes a radiator to become very cold by changing the gas between high pressure and low pressure, a liquid and a gas. Air from outside the vehicle is then blown over the radiator in order to chill it, and this is where the ice cold air comes from.

If it causes you problems, there is probably mold on the radiator/heat exchanger which needs cleaning off with a bacterial cleaner.

[dogbot]

The air it produces is still rank.

I've yet to be in a car with aircon for long that didn't make my eyes water.

[Daimo]

It does decrease fuel economy, fact. In fact, by a good 5mpg in the various cars we've owned.

Likewise cruise control uses more fuel.

Ditto on excess weight, tyre pressures, even the engine being kept serviced (thicker oil = Harder crank rotations = more fuel burnt).

So yes, they are right.

As for windows being open, the electrical side of a window opening is hardly anything. Far far less than an AC unit. The worst side effect is the increased drag of the airflow moving into the car and not around it, but this is far far less than an AC unit, or even having pressures that arn't right in the tyres.

[MinhDinh]

Well, modern day cars have MPG readers so they are probably following that.
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Hit the G spot.

[J4mes]

It's generally because people either don't use it often enough and the matrix goes moldy or because people never bother to clean the system. These are good, have used them a few times on various cars to get rid of the rank smell.

[binge]

[binge]

[colin1]

[D O G]

Mythbusters tested this. They found that A/C is more efficient than driving round with your windows down...

https://en.wikipedia.org/wiki/MythBusters_(season_2)#AC_vs._Windows_Down

[WildGoose]

Most inbuilt MPG calculators are a bit shit, and should only really be used as a guide.

If you actually do the sums the old fashioned way to give your average MPG over a tank, you are not going to lose 5mpg between a tank full using the air con and a tank full not using it.

Cruise control should also use less than manually holding a speed with the pedal. 100 motorway miles at a constant speed with cruise control would provide better economy than 100 motorway miles attempting to hold a constant speed with your foot. If it doesn't your car has a shit cruise control system.

If you use cruise control on a hilly twisty B road then it will use more as it can't see the terrain ahead, and adjustments made are based on what it "feels" the car is doing, which is usually too late or overcompensating.

Do a full journey with both front windows open I would imagine would make a significant difference in terms of drag, but I haven't tested this.

Biggest factors are driving style, weight and rolling resistance (tyres).
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So in other words, he stopped you for being flagrantly in posession of a motorcycle in direct contravention of the Hippies, Darkies and People Whose Face I Don't Like The Look of (Police Powers) Act. 1976

[10 pence Short]

I've gone from an '04 to an '06 Transit. The '06 with air con does exactly the same miles per half tank as the '04 did.
However with this one, you can tell when the air con compressor is engaged as the thing slows down considerably. It's leased so asked the ford stealers to check it out and got the standard "they're all like that" reply.

So I suppose the van goes slower when the air con is on so the fuel consumption stays the same.
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I haven't had a cont all day, drinkstable.

[colin1]

[Suntan Sid]

Why anyone in the UK needs AC is beyond me.

So for the two months of the year when it isn't pissing down or blowing a gale or freezing your nads off, and the sun finally shines for a day or two, you might, If youre bleedin' lucky, get 25˚C.

Grow a pair, the fookin' lot of ya!
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"Everybody needs money, that's why they call it money!"

[Ichy]

My car is about 4 months old and I can't tell the difference if I have aircon on or off, the most I've seen it differ on a 20 mile journey is only 1 or 2 mpg which is about the same difference as having a full tank of fuel. Never tried it with the windows down, its too cold. Cruise control is much worse at about 5mpg lower.
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https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

[Irn-Bru]

I love A/C, the air it produces is like pure fresh air in my opinion, I love it My current car doesn't have it but if it did I'd probably hammer it most of the year just because of the freshness of the air.

I have one of those portable A/C units in my room for over the summer months, feels like walking in a freezer when its boiling outside. Loud as f**k though.

As for fuel consumption... pretty sure they did the myth on mythbusters, can't remember the outcome though.
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KTM 990 SMT & Suzuki DR-Z 400 SM

[Blau Zedong]

Wouldn't own a car without AC these days. I like it to be bastard freezing in my car, starting around this time of year. I've actually had cars off the road in the past awaiting attention to the AC
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[Daimo]