Is it more economical to drive with the window open, or keep the windows all closed and put the air con on?
Are there any stats on fuel consumption when the air con is on?
|
I have read previously that its a/c on and windows shut for max econ.
--
Espada III - well if you have a family and need a Lamborghini, what else do you drive?
|
I remember seeing a thread about this a little while ago, but my inept forum searching skills failed to find it!
The best economy is when you have windows up and air-con off!, but I wouldn't torture myself this way!.
When you switch on the air-con, the extra load on the engine results in a drop in fuel efficiency.
When you open windows, you increase the aerodynamic drag, thus resulting in a drop in fuel efficiency.
I don't know the numbers off the top of my head, but, if you are travelling slowly, then the change in aerodynamic drag is small, and having the windows open shouldn't harm mpg too much.
At higher speed, the increased fuel burn from the large aerodynamic losses makes having the windows open an undesirable option, and air-con is the more efficient option of the two, as Espada has suggested.
Number_Cruncher
|
|
|
|
Shortly after I started driving 30 years ago, I did a lot of long distance driving. I thought it looked cool to drive with the drivers window down in all weathers except rain and extreme cold. Net result is that my right side of my face is now sensitive to wind (cannot remember the medical term).
So Xileno drive with your window closed and turn on the aircon, as otherwise you might start suffering with this problem.
--
Roger
I read frequently, but only post when I have something useful to say.
|
Shortly after I started driving 30 years ago, I did a lot of long distance driving. I thought it looked cool to drive with the drivers window down in all weathers except rain and extreme cold. Net result is that my right side of my face is now sensitive to wind (cannot remember the medical term). So Xileno drive with your window closed and turn on the aircon, as otherwise you might start suffering with this problem.
Or you could do what my wife does, and drive with the window open and the aircon on.
Shakes head.
|
|
|
well I can offer proof.
The touran, long perfectly flat road, no wind, very hot, crusie control 70 mph.
Instant drop of 6 mpg on instant readout with windows down. Repeated experiment several times in the space of a mile. Always consistent, 6mpg drop.
Of course best fuel consumption is windows UP, aircon OFF, and ventilation set to recirculation (ie no fresh air in),
Thats one stuffy motor!
------------------------------
TourVanMan TM < Ex RF >
|
My aircon currently needs regassing, and the heater air distribution box currently has a snapped control rod, so it will only blow air onto my feet, which is really handy in this weather! :o( . I really must get it fixed!
So at motorway speeds I open the passenger side front and rear windows about 30 to 35mm (leaving drivers side closed). This creates a swirl effect inside the car and I get a pleasant draught on the back of my neck, and I can still hear the stereo. Not ideal but it works in the circumstances. And because windows are only open a small amount, it doesnt seem to affect consumption.
It amazes me when I see people doing 80 on the motorway with windows fully down; must be like a hurricane inside the car..
|
How frequently does a 3.5 year old car need re gassing???
What sort of cost and where is the best place in Surrey to get it checked out??, and is it something that is checked on services?? and finally how can you tell when it neeeds re gassing.
If anyone can help I might be able to tolerate this heat.
|
I short, it needs regassing whenever it stops getting cold. My car is 6 years old and is still ice cold, my Dad's 8 years old and still perfect. But my mate's car is 3 years old and needs regassing.
You can get thermometers and stuff to really test but if it's not cooling you anymore, it needs gas.
No idea about Surrey regassers I'm afraid.
|
thanks for that but how much will regassing cost, roughly, does one have to take it to a main dealer or are there independant specialists, and what about those boards tied to lampposts, advertising re gassing, around London offering to do it - any good??
|
|
If you are going to get the aircon regassed then get the aircon hoses replaced at the same time. With the new gas the old hoses will be under more pressure and likely to blow out.
|
|
|
|
Shortly after I started driving 30 years ago, I did a lot of long distance driving. I thought it looked cool to drive with the drivers window down in all weathers except rain and extreme cold. Net result is that my right side of my face is now sensitive to wind (cannot remember the medical term). So Xileno drive with your window closed and turn on the aircon, as otherwise you might start suffering with this problem. -- Roger I read frequently, but only post when I have something useful to say.
Bell's palsy, I believe.
It's a stupid activity nowadays driving with any window open especially if you have a car with aircon. It is noisier to have the window open, you never know what may come through the open window and you also let others know your/one's bad taste in music, especially if the volume is turned up too much on the ICE.
|
Look the roof of my car is going to blow off unless I hold it down with my hand while going along
OK?
------------------------------
TourVanMan TM < Ex RF >
|
Look the roof of my car is going to blow off unless I hold it down with my hand while going along
Surely the company could give you a Capri in which to do this properly?
But you probably have to supply your own sideburns
|
|
|
|
|
Audi designers are obviously taking this to heart! Taking the A2 above 30 mph with a window open was painful on the ears, the A3 is good to no more than about 40.
|
|
What about convertibles with the roof down? All I know is that my MR2 T-bar will do about 10mph less top end with the roof removed, no idea about consumption though.
|
|
Do all cars make a nauseating Wubba Wubba Wubba sound when driving with one window open or is it just mine? usually when small child opens rear window with her foot and can't wind it back up again. grr.
|
Mine does that too. I think its to do with the rear haed rests trapping air behind them.
Thankfully I have slim arms so I can reach back and wind up the rear window on the drivers side - whoneed all round leccy windows eh?
|
|
|
It's an acoustic effect, the car interior is behaving as the inside of a Helmholtz resonator - exactly the same physics as when blowing across the top of a milk bottle and producing a note.
As there is a large volume of air inside a car, the "note" is very low frequency. You can reduce the annoying pressure fluctuations by simply opening any other window by a small amount, or, sometimes, in the case of the sunroof, by closing it a little.
Number_Cruncher
|
|
|
|
|
|
|
This was tested last season on mythbusters. IIRC their conclusion was that up to a certain speed (45mph with their cars) drag caused by open windows wasn't enough to have any massive impact on fuel efficiency and fuel consumption was marginally better with windows open. However at motorway speeds aircon on/ windows closed used much less fuel than car with opened windows.
Their test run with windows closed and aircon switched off however shown 15% better fuel efficiency...
--------------------
[Nissan 2.2 dCi are NOT Renault engines. Grrr...]
|
Very interesting thread.
What about sun roofs?
Got a lift once between Reading and Theale - there was an outfit called the Halfway Garage I think - in a Lagonda V12 with a somewhat naff postwar body on it, built up from total silence to muted thunder, airstream over 80 or the engine at last announcing its presence, didn't last long enough to sort them out... Sublime. This in about 1958 to 1961 I guess.
|
Bring back opening front quarterlights!
--
L\'escargot.
|
Bring back wind-up windscreens.
|
What about the air deflectors that could be fitted to front windows in pre-aircon days; however I'm sure that I saw some advertised recently (possibly for a Ducato?)
I think they were advertised as improving fuel consumption.
----------------------------------------------
One mans junk is another mans treasure
|
|
|
|
