Rep Power: 285

windows up and a/c on

or

windows down?

 
Rep Power: 0

EDITED* I was wrong, windows up and AC on or will use more gas than windows down and AC on. It was just on mythbusters.

 
Rep Power: 0

Having the windows down causes a significant increase in drag, this will definately negatively affect your gas milage, especially at higher speeds. Windows up, A/C off will get you the best mileage, but I wouldn't worry about the A/C much, comfort is worth the extra .5-1 mpg difference.

 
Rep Power: 347

turn on the fan, close the windows. That should be good enough for the best gas-mileage without giving up too much comfort.

 
Rep Power: 0

high speed on the freeway - windows up a/c on = better gas mileage than windows down and a/c off.
low speed on the streets - windows down = better gas mileage than windows up and a/c on.

but windows up and a/c off will give you the best mileage on any road!

 
Rep Power: 276

Actually, you guys will get the answer to that question soon. The show MYTH BUSTERS is doing that topic on the next episode.

 
Rep Power: 285

lol thats why I asked. Just to see what people said before the show

at 45 mph the best was windows down

 
Rep Power: 285

try that in the durty south on a summer day with the humidity making it feel like a steam room

 
Rep Power: 347

Well, of course, in extreme cases, thats why I'm glad we've got those micron thingys standard on the AC.

I grew up in the Philippines, a third world country far closer to the equater, where the most common fuel is diesel. I gotta have my air con, but when the weather permits, I go fan only.

 
Rep Power: 347

Hmm... I just saw this episode on TV. I looked it up and apperently, I was the last person to post up here.

They did two Explorers against each other one w/ AC the other w/ windows down, and the one with the windows down got better gas-mileage...

 
Rep Power: 333

My personal experience from driving 120 miles a day is this.

I get the absolute best mileage on the interstate at 85 mph with windows up and a/c on

any other combination i can drop an easy 2 mpg

 
Rep Power: 303

Wow, old thread.... Anyway, our cars use scroll compressors which are VERY efficient and don't put much drag on the engine. A ford exploder uses a rotary piston compressor. Whole different animal. If Mythbusters tried this with a civic, the outcome would be different. I agree with clownprince based on my own driving as well.

 
Rep Power: 334

would also vary is its a coupe/sedan/suv/truck as some cars have larger windows like coupes over sedans?



best gas mileage: roll window so it has a 2" crack, take a solid smooth board and let the air bounce off that to drivers face/head. then turn a/c off and your game haha

 
Rep Power: 347

I was wondering is this with or without the vents closed?

The AC wouldn't have to work as hard if the car has circulating air while the fan doesn't have to work as hard if the vents were open and natural air were coming in...

 
Rep Power: 272

Who cares? We already get great gas mileage!

 
Rep Power: 320

I saw the Mythbuster things a long time go and called total BS then and still do. First of all, the whole theory of windows up and AC on gets better gas milage is based on the fact that most cars today have a low coeficient of drag, i.e. they are very smooth when the air is passing over them thus creating less resistance to the air and hence it easier to push the car through air if it has low coeffiecient of drag. An SUV has a HUGE coefficient of drag, so right there they haven't even followed the myth, how can you bust a myth when you don't even know what the myth is. I like mythbusters and all, but they did a bad job on that show.

 
Rep Power: 347

I care cuz I'm the kind of guy that would buy a Prius and mod that crap out of it to get more gas mileage...