AC or open windows for MPG

There have long been battles between people investigating A/C vs. use of windows....
Read more at http://blog.gasbuddy.com/posts/The-end-all-verdict-to-A-C-vs-windows-down/1715-457041-563.aspx

http://greenliving.about.com/od/travelinggreen/a/Air-Conditioning-MPG-Gas-Mileage.htm

In the end it depends on the type of vehicle, and the type of driving.

 

Mythbusters did an episode on it. It didnt make any difference with the AC on or not.

 

Well then my guess is that Mythbusters did not do very good research. Logic alone would tell you that it is not exactly the same.

 

Idk, I've seen a lot of mythbusters and they go to the extreme to prove it wrong / right.

 

Uh no. The vehicles they used were exactly the same and driven at the same speed. These were chevy suv's I believe. They concluded that at speeds under 50mph it was better with all the windows down, then with the ac on. but at speeds over 50mph to have the windows up and ac on then all the windows down.

 

New here...but happened to see that episode of the Mythbusters. And never watched another afterward.

Drag is proportional to the square of velocity. So the drag at 35mph is less than half of that at 55.

The Mythbusters did their first test using mass air sensor data from Ford engineers at 50-something MPH. A/C won that test. They were destroying tires at that speed, so they opted to do their second "challenge" test at 30-something MPH. I forget if it was break even or if windows-down did better...but in any case it was a different result.

They then decided their "real world" test trumped the "fancy computer" test, and gave that result.

At first I thought they were idiots, and hadn't any research. Then I thought about it some more and realized there was no way the Ford engineers hadn't explained it to them.

I've seen the "Mythbusters" referenced on about every board I've ever read. They've literally created their own myth.

The answer of course is lower speed = windows down, higher speed = A/C on. Where that trade-off point is will be vehicle specific.

I loved watching Mythbusters until I saw this...couldn't stand to ever turn it on again.

 

Haha! It was so long ago. I can't even remember anything else about the Mythbusters episode. Oh well.

 

haha is this even a real post??? Worried about the difference of having your window down or AC is better on MPG's?? lol let me guess..... maybe .5 mpg's a gallon one way or the other, you may save $.20 on your next fill up..... but by all means...

 

Yes. I'd guess that the dividing line is between 40 and 50 MPH, depending on vehicle specifics. AC is also quieter and reduces humidity. That's enough for me.

Mike

 

If it s hotter than hell out then I will have the AC on. As a matter of fact I always have the AC on, summer, winter, spring and fall. I like conditioned air.

If I were that worried about MPG then I Would have bought a smart car or a Prius. Then I would still roll my TINTED windows up so somebody I know wouldn't recognize me.

 

I don't see a problem with this post and this members question. For once this is something different than the usual, " will these wheels fit my truck?", or " what is a good cheap lift for my truck?" threads. Since gas isn't going to go down in price some people just want to know how they can get the best with what they have. I personally believe the gains will be more than .5mpg, between 1-2mpg. Anybody could test this themselves and it is really easy to do.

 

Will read more later.

Just remember that running the ac is beneficial to the seals. Or so I was told

 

True.

Periodic use will atomize the lubricants embedded in the refrigerant in the system. This then gets carried around during circulation, which coats the entire interior of all cooling system parts. (including the seals, but also just as important, the compressor bearings)

 

I was taught a few years ago by one of my former bosses "Windows are meant for seeing through, nothing more" A/C on, windows up FTW

 

In winter, any time you are on defrost mode, your AC is on. Summer its hot, your AC gets used. Not many people leave their AC off for huge periods of time.

 

Apparently its almost a wash but they say A/C. Windows down creates more wind drag...

 

Does it help the baby seals become more slippery and therefore harder to club?

Comfort trumps the miniscule bump in gas mileage, just remember A/C prevents swamp ass, but Taco Bell promotes it.

 

You should totally apply for Mythbusters, it sounds like your knowledge and experience can finally bring some truth to the show.

 

A/C...we live in Colorado Springs, and it's duuuuuuusttttyyyyy everywhere! I keep the windows up unless we're in the mountains, where it's worth hearing and smelling what's outside the truck.

Oh yeah...this was an MPG question...