Do I need to have my new 2 Eco looked at?

Have you tried either using the trip meters or the "to the Flag" setting?
It would take a large mpg change to affect overall mileage. Your Eco can likely go faster than your c could for highway driving.
Are your tire pressures correct? That can have a large impact on mpg.
Where in the world are you located? Many US localities are experiencing record cold. H sometimes struggle to keep my Two over 40 mpg lately.
In Oct 2016, brand new, by Two got 59 mpg on the 150 mile highway drive home.
It may be normal, with cold weather & winter fuel as you adjust to the car.
IF you find it sluggish, try Normal drive mode.
Is the climate control on ECO (ECO beside the fan speed) and Auto? Heating uses more mpg than air conditioning on the Prius.

 

FWIW, 40 mpg displayed is very likely less when calculated.

 

how many tank fulls have you added, and what was the calculated mpg of each?

 

Press the "TRIP" button on your steering wheel, and it will give 4 or 5 options - one has a picture of a FLAG. That keeps track of JUST your current trip since you Powered ON. It resets every time you re-start the car.

Best indication is to FILL the tank to the first click - drive at least ½ a tank, re-fill and use a calculator/spreadsheet or long division to calculate it.

The dashboard display computes it by inputs from various sensors, none of which are as accurate as your Wallet - the dash display seems to be between 5 and 10% optimistic.

 

It may have also included people test driving it hard. It takes a lot of trip economy to change the total average.

 

you could easily have a brake dragging or something. take it in and let the dealer go through it thoroughly.

 

All the things above mentioned I didn't see the heater listed. With the heat turned up the engine will run just about all the time.
I make a local trip of 25 miles today and got mid 60's at 37 degrees. I live east of you in Indiana. My gas mileage jumped just because of warmer weather and not much wind.

 

I mentioned at the end of post 2 that the heater reduces mpg more than AC.
You make a good point that running the heater cools the engine faster making it run longer and more often.

EDIT: Last winter I was usually able to keep indicated mpg above 50. I have some days in the 40s this year with an occasional one in the 30s due to the cold weather.
In the summed I usually keep it in the 60s

 

Heater use and engine shutdown are definitely linked, on our 3rd gen, in particular while the car is partially warmed. Roll up to a red light with blower going and temperature set moderately warm, engine will often keep running. Shut the ventilation system right off: engine will stop. Once the car is more fully warmed it'll typically shut down at stops in either condition, but just saying.

 

On the Gen 3 pressing the ECO button would shut off the engine in this scenario, on the Gen 4 using the ECO heater setting does this.

 

A few things to unpack here. From what I'm gathering, you have been getting 41 MPG on surburban streets during fairly cold winter weather in Chicago. It's also been very windy. What are your trip lengths like? 41 MPG is perfectly reasonable for winter weather and short in-town trips.

If you were driving fast on the highway, again during the late fall/winter, 45ish MPG also seems right on the money.


Think back to when the 2012 C was new, when were you getting 50 MPG? What time of year? What was the weather like? Were your driving habits the same?


I think its at least 80% odds that the MPG you are observing is completely attributable to the environmental conditions you have been driving it in, the length of trip, and your driving style


My 2 Eco went from 65 MPG in the summer months to 60 in the fall and now in December/January it is in the low 50s, and in the high 40s on many days. Today I only got 44 MPG going to work, because of the strong headwinds

 

I usually have to drive at least 20 miles before I can show respectable fuel mileage in the cold weather. Anything shorter and I am in the 40's. We know the engine has to come up to temperature but all the moving parts are cold and I never heard about the traction battery, how long does it take it to get up to an efficient temperature.

 

Some may depend on the internal temperature - there was talk by some who don't turn the Climate Control on but use the seat heaters being more economical. Not sure - we don't get the cold you do there - it was close to 40 deg CELSIUS here yesterday.

 

While the US has been seeing record cold you guys are breaking all time high temperature records.

 

I'm sure it's not true in your case, Alan, but some of your compatriots must be acclimatising for the afterlife!

 

And where does that place me? 9F (-13C) here this morning.