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Author Topic: Windows Open, No AC Back to Topics
GSDMan

Rookie Author
Maryland

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Message Posted: Sep 12, 2013 9:19:24 AM

I didn't want to hijack another posters thread and I don't recall this being addressed.

I know about the drag of open windows at highway speeds versus running AC, blah, blah, blah. What I'm wondering is can we alter the airflow enough to mitigate the increased drag with the windows open? My Ram has a sliding rear window and I noted with it open it significantly calmed down the air currents inside the truck. Going on the premise that it takes energy to move air and it appears airflow through the truck is lessened, or at least less turbulent, with the rear window open, could I be getting better mpg this way?

I'm doing a mileage test with 91 octane and a ECM tune right now so I'll test this after that but I'm wondering if anyone's experimented along these lines?
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Awing1
Sophomore Author Ontario

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Message Posted: Apr 14, 2014 9:10:40 AM

I would use AC on the highway since it will create noise and resistance to go forward. MPG would be similar for both AC and opening window.
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drgeeforce
Sophomore Author Los Angeles

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Message Posted: Apr 14, 2014 9:06:10 AM

Having windows up or down has neglible impact on MPG. The A/C does reduce MPG.
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deant99
Champion Author Ontario

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Message Posted: Apr 13, 2014 9:15:25 PM

AC on high way open rear windows in city
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dgsteven
Champion Author Los Angeles

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Message Posted: Dec 30, 2013 3:57:28 AM

A/C is better
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PaylessKY
Champion Author Kentucky

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Message Posted: Dec 28, 2013 10:23:18 AM

In the summer time I use the a/c.
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DrThos
Sophomore Author Madison

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Message Posted: Dec 25, 2013 4:07:28 PM

Top down a/c off, unless it is really hot then I will use the a/c and still keep the top down.
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dallfo
All-Star Author Denver

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Message Posted: Dec 25, 2013 10:51:52 AM

Merry Christmas.
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RS101
Champion Author Minnesota

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Message Posted: Dec 25, 2013 9:13:37 AM

Merry Christmas
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johnny81356
Veteran Author Nebraska

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Message Posted: Dec 25, 2013 3:52:46 AM

I use ac most of the time in hot weather
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twt
Champion Author Virginia Beach

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Message Posted: Dec 25, 2013 2:41:39 AM

I just do whatever feels comfortable. I don't use a lot of heater or AC, so the difference in gas mileage, is minimal to me.
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Maintroll
Champion Author Lexington

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Message Posted: Dec 21, 2013 8:48:40 AM

I leave the air on year around only in winter I have the dial set to warm which in turn keeps the windows clear. Try it, you might like it. This is an old bus drivers trick in case you wondered.
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probedjg2013
All-Star Author Louisville

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Message Posted: Dec 19, 2013 7:55:07 AM

if it is hot out I always use my ac, but when I can leave my windows down I will always do that
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Glasman
Champion Author South Carolina

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Message Posted: Dec 19, 2013 2:38:27 AM

now you tell me the door glass is adjustable , well I'll be dipped.
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pghbill
All-Star Author Pittsburgh

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Message Posted: Dec 18, 2013 12:59:41 AM

no way, ac all the time
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carinthuist
Champion Author San Francisco

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Message Posted: Dec 17, 2013 11:42:54 PM

vent only
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BaieCRD
All-Star Author New Jersey

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Message Posted: Dec 17, 2013 6:04:56 PM

Prefer fresh air vs forced air
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buddy_maynard
Sophomore Author Cincinnati

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Message Posted: Dec 17, 2013 5:16:14 PM

I use the AC to keep my boys (4 and 2) cool.
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RalphHightower
Champion Author South Carolina

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Message Posted: Dec 17, 2013 5:57:57 AM

I use AC
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randy3116
All-Star Author Tennessee

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Message Posted: Dec 16, 2013 11:26:30 AM

i prefer fresh air but will use a/c when temps rise over 85
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davisadm
Champion Author Los Angeles

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Message Posted: Dec 16, 2013 9:49:29 AM

I like it quiet, without wind buffeting when I drive. Windows will stay closed, a/c, air, or heat will be on as needed.
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WEPSMAN
Champion Author South Dakota

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Message Posted: Dec 16, 2013 9:08:36 AM

I would rather be comfortable than worry about saving a couple cents on gas.
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herbiepopnecker
Champion Author British Columbia

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Message Posted: Dec 9, 2013 1:01:11 AM

It's -20, I don't think I'll drive with the windows open....
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Camry05
All-Star Author Indiana

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Message Posted: Dec 8, 2013 7:05:30 PM

haven't done a mileage test that way, maybe something to send to the mythbusters
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ny10
All-Star Author Virginia

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Message Posted: Dec 6, 2013 10:17:24 AM

In highway, I think it is better to use A/C than opening windows.
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Lambang
Champion Author Illinois

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Message Posted: Sep 18, 2013 2:33:26 PM

When it is hot out the AC is on and the windows are up.
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Chazzer
Champion Author Nevada

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Message Posted: Sep 18, 2013 1:47:08 PM

Widows open around town. Windows closed out the interstate w/AC on!
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OceanArcher
Champion Author Mississippi

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Message Posted: Sep 18, 2013 10:57:37 AM

Windows open, huh? That driver doesn't live where the "luv bugs" flourish ..
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dvc2
Champion Author Oakland

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Message Posted: Sep 16, 2013 1:42:02 AM

Closed with the air on.
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OilerFan
Champion Author Tulsa

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Message Posted: Sep 15, 2013 8:54:38 AM

In good weather, I drive with the windows down, except when at high speeds (too loud).
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Bus936
Champion Author Lexington

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Message Posted: Sep 15, 2013 8:18:21 AM

The vehicles most of the time run far more efficient with the AC on and there isn't that much difference in gas mileage. I run mine year around in order to keep the windows defogged in winter, except with the temperature on a warm setting.
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Glasman
Champion Author South Carolina

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Message Posted: Sep 15, 2013 7:51:18 AM

like to see you travel across Arizona & parts of New Mexico in August when the temps are triple digit without air.
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lyanMI
Champion Author Detroit

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Message Posted: Sep 14, 2013 7:20:53 PM

mostly AC
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bluenvoy
Champion Author Nashville

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Message Posted: Sep 14, 2013 9:37:08 AM

AC. Too much dirt gets in the car when I drive with the windows open.
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Dustin19d
Champion Author Fayetteville

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Message Posted: Sep 14, 2013 6:25:45 AM

I have a bone stock 93' Civic with 238K miles that averages 39.4 MPG over the 50K miles I have put on it. It has no AC so the windows are down 9-10 month out of the year. Not to bad considering the EPA rating is 29 city 36 highway. Windows up, windows down, AC on, AC off it doesn't matter. What matters is your location and how YOU drive.
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sagnat
Champion Author Riverside

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Message Posted: Sep 12, 2013 10:19:03 PM

If i am running at highway speed, as long as it isn't too hot I will put all four windows down about 3 inches and it doesn't seem to effect my MPG. At speed, windows down can create drag, while windows up leave basically a lick surface which gives better MPG even with the AC running.
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MTK143
Veteran Author Pittsburgh

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Message Posted: Sep 12, 2013 3:17:55 PM

windows
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KansasGunman
Champion Author Kansas

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Message Posted: Sep 12, 2013 12:37:01 PM

I'd rather be comfortable with the air on thanks...

Rose up above living in sweat in the late 60's...
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Zennyboy
Veteran Author Toronto

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Message Posted: Sep 12, 2013 12:25:31 PM

mythbusters has disproven your theory about "wind drag" with windows open.
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GuitarmanMS
All-Star Author Mississippi

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Message Posted: Sep 12, 2013 11:24:32 AM

I have read that on the highway if you have your A/C on low it is more fuel efficient than having the windows down but in city let them down if possible.
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dontuknowOH
Champion Author Ohio

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Message Posted: Sep 12, 2013 10:00:58 AM

Tests can be beneficial for economy/comfort, Good luck That's how DIYers get it done, not always the best but affordable, errors are common.

It sort of like a train track crossing, I still stop, look ,then listen before crossing, I'm sure many just trust the gates/signals, and drive on over, I have seen that not work on only one occasion, sounds, visibility, both failed along with the safety stuff, yey the windows were down and no A/C or radio on.

The Driver survived, bruised, in shock, with vehicle totaled, upside down totaled, end to end totaled, right in front of me action on a hot Summer day.

That was about a 7 Mph event both traveling slower than a bicycle rider. Yes if you don't need to run your ventilation blower motor rather using the rear vent window as a negative air pocket, still air will flow threw the regular vents when the windows are up/closed unless blocked at the vents.

Some blower motors are set to run at a very slow speed when turned off only if ign. is on run to safety ventilate cabin while motionless. Older tech. stuff Try testing whether the air at the open rear vent is entering or not but exiting maybe at different speeds.

How do you control head/tail winds at any travel speed for increased mileage driving in the natural? Blank............................ LOL
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