Eco mode should be on or off while driving in the city?

If you are happy with the accelerator pedal response in Eco mode leave it in Eco mode. At 16mph average and 47mpg with AC on you are doing just fine. Eco mode reduces AC output and fan speed under some conditions but if your comfortable with it now don't worry about it.

The mode buttons just remap the rate of change of the pedal position sensors giving Normal and Power faster rates of change for a given pedal movement (first half) than Eco mode. All modes meet at the same full throttle position. No actual change in engine/motor performance happens except for the previously mentioned AC reduction.

 

Keep it in ECO.
Tvoi droog,
c

 

Pajaluista.
Also put more are in the tires between 40 to44 psi all around. it will help with mpg.

 

I leave it in normal all the time since my foot is already used to the pedal travel. It keeps me from constantly looking at the display.

 

You can do exactly what works for you.

I personally use 'ECO' mode when in the town/city, 'NORMAL' mode at all other times other than hills, overtaking etc when I will use 'POWER' mode.

'ECO' mode will also reduce the a/c output slightly.

 

I switched from using ECO to "normal" (neither ECO nor PWR modes on) 2 or 3 tanks back, and have not not noticed a drop in mileage. If there is any drop, it would appear to be very minor. I prefer the throttle response in "normal": too sluggish in ECO.

 

Yes, but will reduce A/C output slightly, as Grumpy said...
I wonder if raising set temp a degree or two in Normal mode will not have the same effect?

 

I agree with all above responses.
Regarding the modes you can have a look here as well how they work:
Operating modes (ECO, Normal, PWR and EV) - Prius Wiki

Regarding how to drive to get best fuel mileage without resorting to advanced hypermiling techniques, you can have a look here:
Tips & tricks for the “normal” driver to achieve satisfying fuel efficiency on the Prius Gen 3 « Prius 3 experiences from Europe

 

Excuse the redundancy, if there is a thread on this somewhere in the forum, but I didn't find anything on it. Is there any problem with using the "power mode" when initially moving away from a stop, and then "undoing" the power button. I mostly just drive in the "no button" mode. But after trying a tankful on "PWR", it's like an entirely different car! I have no problem using the pwr mode all the time, but think possibly I can get the "best of both worlds" by using the pwr to start off and then switch to "just drive' mode......?? Don't want to do the car any harm, and think possibly I'm not. Does anyone have any info/thoughts on this?
Why not drive in pwr mode all the time...? Because you have to think to push the button each time you start the car, and in the extreme name of economy you would be more likely to remember to push the ECO button. But sometimes when someone is pressing me I would like to use the pwr mode to just clear out ahead of them. I have tried this and it seems like the swiftness of getting to speed in pwr mode does not take the mpg penalty that the "just drive" mode does. I know it's simply "putting your foot into it" rather than anything mechanical, but it seems like it works.....
Anyway just want to know I'm doing the vehicle no harm to switch pwr mode off after getting to speed.

 

Going from Eco to Normal is a noticeable mpg decrease for me. When it's 42 degrees (108F+), I'll indulge and start out in Normal and then switch to Eco.

As others have pointed out, the difference is with the AC and the feel of the petal.

My fuel economy change is about 4%. Non hybrids most likely wouldn't notice the difference. I don't worry about it that much and am willing to pay the extra.

 

Going from ECO to Normal did not result in any change in my case. I belive that this is due to the route I have to travel every day. It's mostly highway where ECO doesn't help much if any.

 

Guys, again.
The modes *essentially* change the gas pedal response but not just that.

In PWR the engine tends to stay on when releasing gas to be ready to provide torque as soon as the gas pedal is pressed again - essentially everything is geared to give the fastest response to the gas pedal and keep the battery more charged. Turning off the ICE when releasing the gas pedal would require restarting (albeit very fast) the ICE once again. Everything else is the same as in "normal".

In Normal the pedal response is "normal" (i.e. linear) and A/C and ICE behave "normally" (i.e. the ICE will turn off when releasing the gas pedal if battery conditions allow and the A/C works "normally").

In ECO the pedal response is subdued and the A/C will throttle down the compressor, reduces the fan speed (to reduce the "wind-chill" effect) in summer and in in winter it will also reduce the fan speed and therefore tend not to use the ICE so often as in Normal to keep the cabin warm. I.e. the A/C works in a more "moderate" fashion.

In all 3 modes, the overall power is always available - acceleration by flooring the gas pedal will be the same (there are videos about this - see the Wikia entry posted above) in all 3 modes.

So - what is best for this or that situation?
If you drive 95% of the time on the highway at constant speed, the 3 modes will not do any difference at all, except in summer. (robby3 above is one case)
If you drive 95% of the time in town, ECO mode will help reduce fuel consumption because of the throttling down of the A/C behaviour and, for certain drivers and if traffic conditions allow, to smooth down the overall driving. The killer of MPG in town is not having a smooth drive. Breaking abruptly will kill MPG (everywhere, actually, but more so in town).
There are those who manage with PWR mode to get good MPG in all traffic conditions, and like the idea of not pressing too much the accelerator to get a good kick. There are those instead who prefer ECO to have more control of the gas pedal. Others simply stay in Normal mode.

In my personal case, traffic patterns and driving style, I am perfectly fine with ECO and I find PWR to be too much and increases my fuel consumption.
For others it would be maybe completely the opposite.

It is essentially up to you. Try what works best with your driving style and traffic conditions. I am not a fan of changing the mode continuously during a drive, but if you want you can do it. Everything is managed electronically so nothing will get broken (maybe the button for using it too much! ). And most of all, simply drive the car and don't freak too much about MPG - as long as the ride is smooth, without unnecessary accelerations followed by hard braking to reach as fast as you can the next red light, the Prius will prize you with excellent fuel consumption. If you want to kill yourself with MPG, then go ahead with the "hypermiling" techniques, but then likely the modes will not help you at all.

 

I find it's easier to glide in ECO. Anyone agree?

 

It depends on how much you are "feather light" with the foot - you might be able to do that also on PWR - but surely ECO helps...at least in my case...!

 

Yes it is, that's one of the main reasons I prefer ECO.

ECO provides finer control during the first half or so of gas pedal travel. Normal is kind of like the Gen2 Prius. Power gives you most of what is available during the first half of pedal travel and not much change after that. Power mode is similar in feel to most other cars.

At full throttle all three modes provide the exact same amount of power. ECO provides more economical control of AC.