A/C and gas consumption

[ToyotaToday]

Has anyone done any test on gas consumption when A/C is ON versus when A/C is OFF?

I went to the dealers and the service advisor said the A/C doesnt really consume that much more gas, he said about $5 more per month during the summer months. Of course, every car is different and depends on how long you leave it on and outside temp, etc.

[knotquiteawake]

When i had an '84 Celica, a 4-banger, the a/c made a difference i could feel as far as power goes but i never had a chance to calculate the mpg change. Then when i started driving my 81 cressida, an i-6, i could hardly tell the difference between a/c on and a/c off. So i just guessed that the bigger the engine or more torque the engine had the less effect things like a/c, headlights, ect... made of mpg.

[simplyxtrippin]

you can definite feel teh difference in power. i've heard that research has never really had any solid data wether window being down (ofcourse if u not using the a/c ull be putting the windows down) is better than using the a/c.

i've seen the episode of mythbuster where they experimented on this problem. they checked at different speeds. did not really prove anything since the difference in mileage is almost the same. but in there data, it seems that the faster your going the more gas you'll save when your using the a/c. and when you going slow, rolling the window dows is a little better. i guess air resistant had something to do with that.

since the difference is very minimal and does not really matter as much, i say just go with what you are most comfortable with.

[jhbhatia]

I do a lot of highway driving. In the winters i can get 540-560 per full tank of gas. In the summer months (i'm in Houston, so a/c is not a luxury, its a necessasity), i attain close to 500 miles per full tank. I usually start off at the fan speed of 1 (one dot) and then lower it to "low" setting. It doesn't make a big dent to me personally on mpg's, but if you have people in your car and its dead summer and your a/c fan know is at 2'nd setting...you can feel a big dent in power!