What saves more gas…………..what proves it?

depends on your speed:
At highway speeds, ac is better.

In slow traffic, windows are better…

buy a scooter

Neither. Myth, myth, myth…Use your airconditioner guilt free.

While the A/C compressor does pull power from the engine wasting some gas, the effect appears to be fairly minimal in modern cars. And putting the windows down tends to increase drag on most cars, canceling out any measurable gain from turning the A/C off.

“Test #4 A/C On, Windows Up vs. A/C Off, Windows Down

Result: Nice in theory; not true in practice

Cold Hard Facts: No measurable difference (unless you open the sunroof, too!)

Recommendation: Please, make yourself comfortable.”

Air Conditioner: Read the entire test:
http://www.edmunds.com/advice/fueleconomy/articles/106842/article.html#test4

windows down below 40 mph and ac on above

you want proof try the test.. buy a tank run with the air on… mark the mileage when you run out mark it down…. then another tank and drive with the window down til you run out of gas again then mark down the mileage and you will have your answer…..what you will save or wont save will be in tenths not gallons…. tires air to the max pressure and tune to its best… dont take off fast and coast to a stop as much as you can

Just read this morning that the Air conditioner doesn’t use much gas at all and they say go for it.

windows and buy a hybrid

Some tips for help with mileage:

keep your tire pressure as high as your owners manual allows.

drive carefully. accelerate slowly.

when you see a stop (red light, etc) ahead of you, immediately take your foot off the gas and coast to the stop.

no roof rack

keep the car maintained properly.

If your owners manual says premium fuel required, use it.

on the open highway, drive as slowly as your patience allows. I found that shifting from 75 to 65 increased my mileage by 20%.

Use cruise control. Steady speed helps mileage.

Do not idle. let the car warm only for 30 seconds before driving off. If you are going to be stopped at a long light, shut the engine off.

And the biggest one: don’t drive.