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Author Topic: Which is more fuel effient? Driving w/ windows down or A/C on? Back to Topics
Lynn2go

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Connecticut

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Message Posted: Aug 8, 2012 9:23:18 PM

I couldn't help but think of this, especially when driving on the highway? Because, when you're driving on the highway with the windows down, you're effectively increasing drag on your car, let's say, a full-sized van, for example. Or, are you using more gas driving, in the same conditions, with the A/C on (windows up, obviously), since the A/C uses gas to work. Or, am I totally over-thinking the whole thing? (I hope I explained the two scenarios sufficiently. :) )
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badbobKY
All-Star Author Lexington

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Message Posted: Jul 7, 2014 9:23:24 AM

toss up
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dontuknowOH
Champion Author Ohio

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Message Posted: Jul 6, 2014 3:33:49 AM

In most cases driving in close city traffic at slower speeds the A/C on will use more engine energy. Reasons being the A/C creates more excess operation heat for the present vehicle's coolant system.

Secondary coolant fans run more continuous to handle the extra heat developed, the kind of day, amount of traffic, amount of times your vehicle is running in a slower motion speed, all makes a variable difference in mileage.

Simply vehicles are different along with Driver's comfort choice levels, and the surrounding circumstances ETC. affect the amount of energy needed to maintain the A/C benefit drag on the fuel consumption levels.

Sweating with the windows up/down A/C off can save some fuel, even though you are toting around the extra weight of that total A/C option during possible Stop/Go Traffic and if it (A/C) works properly when on, equals Sad...Very Sad, causing those oil folk's stock to suffer....
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hoopitup2000
Champion Author Virginia

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Message Posted: Jul 3, 2014 6:33:48 AM

A/C uses a lot more in stop & go traffic.
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Floridaman2013
Champion Author Florida

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Message Posted: Jul 2, 2014 12:15:31 PM

With a 4 cylinder, it's a toss up when AC is on as it puts a good load on the engine. A V6 and larger engines won't really be affected that much so driving with the windows closed and ac on most of time will get maximum mileage figures.
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sirreal1984
All-Star Author Indianapolis

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Message Posted: Jul 2, 2014 12:10:04 PM

Windows closed, A/C off is the most efficient. Good luck, Arizona drivers.
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Boyrr
Champion Author Allentown

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Message Posted: Jul 2, 2014 9:03:36 AM

AC
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Awing1
Champion Author Ontario

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Message Posted: Jul 2, 2014 7:33:59 AM

depends on the speed.
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hoopitup2000
Champion Author Virginia

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Message Posted: Jul 2, 2014 6:23:37 AM

On the highway, it's a draw. Around town, windows down is more efficient.
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carinthuist
Champion Author San Francisco

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Message Posted: Jul 1, 2014 2:30:12 PM

ac off windowa up
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dassfg
Champion Author Fort Worth

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Message Posted: Jul 1, 2014 7:58:30 AM

Windows up
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WES03
Champion Author Maryland

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Message Posted: Jul 1, 2014 7:47:30 AM

AC off and windows down about 3 inches at highway speed. Aero drag is negligible and mileage is not affected. At 40 mph or less, windows open.
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dassfg
Champion Author Fort Worth

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Message Posted: Jun 25, 2014 7:58:55 AM

A/C on windows up
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OilerFan
Champion Author Tulsa

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Message Posted: Jun 25, 2014 7:42:43 AM

I prefer to be comfortable. As far as efficiencies, I think it's better to just be easy on the gas pedal.
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MertieMan
Champion Author Lexington

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Message Posted: Jun 25, 2014 7:29:41 AM

Windows up, AC on.
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dontuknowOH
Champion Author Ohio

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Message Posted: Jun 24, 2014 10:07:47 PM

Traveling with my econos at 40 MPH or less, I generally have the A/C on and often my Driver's window open 50% or more while in traffic. At higher speeds window closed, never noticed much difference in mileage relating to that window habit setting.

About a 3% - 4.5% drop when running the A/C over not, depends on highway speed, heat of the day,>>>> due to coolant fans run time intervals and cabin blower speed..../comfort levels of choice....Sun/overcast, ETC.

I never stop the A/C when needed unless I have the low fuel light on and I'm $ broke, same time, along with a sad face showing in my r.. mirror... OPPS!
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GLM4205
Champion Author Toledo

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Message Posted: Jun 24, 2014 6:10:32 PM

Depends on your speed.
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texaskellys
Rookie Author Houston

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Message Posted: Jun 22, 2014 12:44:27 PM

Most of the comments are dead on in my opinion, especially "it depends." Recent tests show that under 35-40 mph, you'll do better with the AC off and windows down. Above that, roll up the windows and turn on the AC. Interestingly enough, the savings will vary depending your aerodynamics. Tests show a 20% difference in mpg for a modern coupe vs 8% for a bulky p/u or SUV.
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eptraveler
Rookie Author El Paso

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Message Posted: Jun 19, 2014 11:17:48 AM

It's my understanding that the A/C's of today are much more efficient than the clunkers of the 60's. Current thinking seems to be roll up the windows, turn on the A/C, and use your cruise control out on the highway.

Around town I would think that windows down would have negligible effect, especially if the temps were bearable.
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Jackson126
All-Star Author Virginia

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Message Posted: Jun 19, 2014 6:37:29 AM

Depends on your speed
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hoopitup2000
Champion Author Virginia

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Message Posted: Jun 13, 2014 6:54:54 AM

It's a toss up . . .
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dontuknowOH
Champion Author Ohio

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Message Posted: Jun 12, 2014 10:36:19 PM

A/C on most usually, my econo doesn't seem to lose much mileage when running the A/C. Yes a slight drop but affordable.
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mnrick041
Champion Author Twin Cities

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Message Posted: Jun 12, 2014 5:46:24 PM

Either way you are decreasing your fuel economy. Personally I just go for the comfort and turn the AC on.
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Les4hdtv
Sophomore Author Alabama

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Message Posted: May 24, 2014 11:48:22 AM

The sun roof is preferred because it is designed to create less drag than a car window and it removes the hottest air which is near the roof.

My first 59 Ford Fairlane 500 Galaxy had 460 AIR - Open 4 windows and drive 60 miles per hour.
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contiki
Champion Author Ontario

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Message Posted: May 24, 2014 7:31:19 AM

Windows are up most of the time.............
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WEPSMAN
Champion Author South Dakota

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Message Posted: May 12, 2014 9:55:10 AM

If you are looking at mileage, both affect mileage. The windows down increases drag and the A/C takes some power from the engine. I prefer the A/C on myself.
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dassfg
Champion Author Fort Worth

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Message Posted: May 12, 2014 7:52:05 AM

Always windows up
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contiki
Champion Author Ontario

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Message Posted: May 12, 2014 6:49:35 AM

A/C on ........
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Jmac2008
Champion Author Missouri

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Message Posted: May 12, 2014 1:16:58 AM

A/C on
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Mikeyl
Champion Author Cleveland

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Message Posted: May 11, 2014 9:18:12 PM

The science has shown MOST CARS are better:

under 45 - windows
above 45 - A/C

But, if it's hot, use the A/C because there is such a slight difference that it really wouldn't matter anyway!
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GLM4205
Champion Author Toledo

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Message Posted: May 11, 2014 8:53:50 PM

At freeway speeds, the AC is more efficient.
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twt
Champion Author Virginia Beach

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Message Posted: May 10, 2014 4:38:26 AM

It doesn't matter, to me. When I get hot, I turn on the AC.
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Boyrr
Champion Author Allentown

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Message Posted: May 10, 2014 3:18:41 AM

If you rot, turn on the ac and drive
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Dennis783
Champion Author Des Moines

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Message Posted: May 9, 2014 7:41:41 AM

For me it doesn't matter, I want the comfort of ac
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MertieMan
Champion Author Lexington

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Message Posted: May 9, 2014 5:08:11 AM

Windows up and the AC on at all times.
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eyegotgas2
Champion Author British Columbia

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Message Posted: May 9, 2014 3:18:21 AM

It would be good to know the real answer to that one
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ace12012
Champion Author Phoenix

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Message Posted: May 8, 2014 1:14:43 PM

a/c on.
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NJDeMarco
Veteran Author New Jersey

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Message Posted: May 8, 2014 11:39:54 AM

With the A/C on.
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OilerFan
Champion Author Tulsa

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Message Posted: May 8, 2014 10:37:08 AM

I would say that it's probably a good idea on the freway, to use A/C.
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Vin63
Champion Author San Bernardino

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Message Posted: May 8, 2014 10:04:07 AM

At freeway speeds, the AC is more efficient.
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dassfg
Champion Author Fort Worth

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Message Posted: May 8, 2014 6:45:03 AM

Windows up is always more efficient
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MertieMan
Champion Author Lexington

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Message Posted: May 8, 2014 5:06:13 AM

It really doesn't make that much difference if the vehicle significant power.
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krazkar
Champion Author Calgary

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Message Posted: May 7, 2014 10:21:56 PM

Don't care. If it is hot the A/C is on.
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OceanArcher
Champion Author Mississippi

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Message Posted: May 7, 2014 6:47:42 PM

Depends on the shape (sleekness) of your sutomobile
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Sugarshaneo7
Veteran Author Michigan

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Message Posted: May 6, 2014 9:56:01 AM

probably depends on the aerodynamics (design) of the car.
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rick_evans
Champion Author Boston

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Message Posted: Aug 20, 2012 1:10:15 PM

Here's what Mythbusters found.
http://dsc.discovery.com/fansites/mythbusters/db/science/ac-vs-open-windows.html
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vghostine
Rookie Author Montreal

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Message Posted: Aug 14, 2012 2:39:28 PM

Windows down for boxie cars means lower mpg while sports car will not see much difference. Aerodynamics change from one vehicle to another.

It all depends on the vehicle you are driving. The type of maintenance you've been doing...how much the tires are inflated... if you have a spoiler or not, if you have the sunroof open or not, if the wind is blowing really hard or not.
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nichols
Champion Author Halifax

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Message Posted: Aug 14, 2012 1:03:29 PM

windows down
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jonjon57
Champion Author Raleigh

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Message Posted: Aug 13, 2012 9:07:01 PM

Windows
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IAMCANADIAN73
Champion Author Ontario

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Message Posted: Aug 11, 2012 1:09:24 AM

Windows
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seabrz7
Champion Author California

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Message Posted: Aug 10, 2012 6:50:12 PM

Since it's 105 today I think I'll keep AC on High.
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