Need Advice.

[Twistoffate0817]

Hello all,

I am now commuting to school three days a week and need opinions on which is better for MPG sake. I drive 50 mph all the way there. I have googled whether or not it was better to drive with the windows down a bit, or the air circulating from the outside with the window up and cannot find an answer that makes sense. My question is...is it better to drive with the window down a bit at 50 mph, or window up with the air circulating in from the outside? Which one will give me the best MPG? Does turning the fan on setting 1, 2, 3, 4 effect my MPG? Thanks!

[Lil Abner]

In my experience, running the air doesn't do anything for economy. And the fan speed doesn't control how much the AC compressor runs. It runs the same regardless of the fan speed.

[sickpuppy1]

If your talking about just bringing in outside air, running the blower wont affect fuel economy at all. running with the window

[SpaceShot]

Either having the windows (partially) down or using the AC will take 1-3 Mpg off your trip average. Going with the windows up and the interior fan turned all the way up doesn't seem to have a measurable affect on trip Mpg.

[Kal-El]

Just be comfortable. If you're very warm or hot, put the AC on. The Yaris's AC is very efficient, unlike the old days when AC really drained power.

I never noticed more than 1 mpg difference. There's other factors that effect MPG more, like simply stop signs and red lights - they waste way more gas. Or even which way the wind is blowing which you can't control.

The difference in AC on vs windows down is extremely negligible.

[malibuguy]

windows up for me at speeds over 35mph

now sometimes if its very nice out, i'll drive windows down 60+...

[Twistoffate0817]

I won't use the AC unless im doing highway because the AC makes my Yaris very underpowered and I have to push the pedal down hard for it to accelerate from a stop. I guess I will try using the air from the outside instead of having the window down a bit. :P

[nessan]

if you are going to open windows as alternative, then I would advice you to keep ac on windows greatly disturbs aerodynamics resulting in reduction in average,

[daf62757]

You might want to also evaluate the terrain conditions. Driving 50 in hilly areas might actually use more gas than driving a little faster. You coast farther if you are going faster and you can go farther up a hill if you are going faster. I have found it to be a real art to squeeze out as much mileage as possible but if you drive the same route on a regular basis, you should be able to master the best speed even with the AC on. I would never put personal comfort over mileage in a Yaris. The difference is just not that great.

[mr9865]

In my ECHO driving 50 mph A/C off got me 54mpg for my hwy trip, doing the same trip at 75 I got 43mpg. Driving slow does help!

[eTiMaGo]

only way to be sure:

1) drive 1 tank with windows down exclusively
2) drive 1 tank with windows up and AC on exclusively
3) drive one tank with windows down at normal speeds and AC on at highway speeds

Keep a log of your fuel consumption under all three scenarios and see which one makes the most sense in terms of economy and comfort :)