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in Brandon, Manitoba. 4 months of temps between -30C and -10C. 90% of the time the car would be running short trips, 5km to work, in regular small city (45,000) traffic conditions, flat terrain? My wifes RSX gets 20 mpg (US) under these conditions.

Once a month the car will travel a round hwy trip of 270 miles, at 70 mph on flat hwy. The RSX will return 33 mpg (US) on this trip.

Wondering if the TCH will provide significantly better mileage than the TC V6 under these less than ideal conditions?

Hi Sbtatter:

___With the price of fuel in your area, a US EPA of 40/38 for the TCH here in the states under ideal conditions, the extremely short trips your wife will be normally driving, and knowing what happens to Prius’ in winter temps, I would be a bit leery given the extreme cold temperatures you experience that far north. Hybrid’s take a harsher hit then non-hybrids in some cases and the Prius’ are very susceptible to a killer cold temperature FE hit. I would say with your wife’s commute description, I would not expect more then 30 mpg’s (probably 27 - 29 mpg’s more then likely) from a TCH during the winter months. I have never driven a HSD equipped hybrid long in colder temps but have read of some really nasty Prius I/II FE when the temps drop below freezing.

___Here is Tony P’s Prius II in the winter months and take a look at the times his tanks average temps drop into the 20 degree F range.

http://www.cleanmpg.com/photos/data/506/Tony_S_-_Year_round_Tank_Data.jpg

___He is a great Prius II driver for this part of the country (just north of Chicago) and if his Prius II is seeing < 42 mpg’s in 15 - 20 degree F temps with longer segments then your wife will be driving, I have the feeling you may see just 27 - 29 mpg’s in those really cold conditions as discussed above.

___I am not a Prius II/TCH expert as my time behind their windscreens usually comes about when conditions are closer to optimal (day time with temps above 60 degrees F) so my estimates would be little more then educated guesses. I hope the Prius II folks will chime in with their own very cold temperature vs. % FE hits to give you an even better idea.

___Good Luck

___Wayne

Thanks very much for the info. Shocking how the mileage varies with the temperature. But maybe my gas powered engine mpg would also follow the temperature? Will I be able to pull that same graph from this site, or was that created in Excel?

Sbtatter,

Not a lot of people think about how cold air and a cold surface (even ice-free) hurts fuel economy.

I suspect if you get a TCH, your FE is going to be better than 80% or even 90% of the other drivers on the road.

You just got me to dream up another solar application - glass roof car to use the sun to heat the coolant in the dead of winter. :)

Hi Sbtatter:

___The one item a Hybrid goes through in very cold temperatures that a non-hybrid doesn’t is that its hybrid HW does not perform up to par if at all (Auto Stop/Lean Burn/EV/ICE-Off on a whim depending on type of hybrid) whereas a non-hybrid just gets the normal cold weather hit. This is where you have to be real careful. If you take away a TCH’s ability to go ICE-Off/EV or run in a semi-efficient mode on the Atkinson intake, you have taken the TCH and made it into a std. Camry for those short trips in very cold weather. The payback may go to nill so weigh the short trips in cold weather when you decide on what is the best automobile for your wife. The TCH may drop you into the teens for the < 2 mile trips and you would not be a very happy camper if this was not pointed out up front. The non-hybrid Camry will not do better but the delta (FE of the TCH vs. the non-hybrid Camry) may get awfully close.

___Good Luck

___Wayne

Hi,

I live in Bangor, Maine which is cold but not as cold as Brandon, Manitoba. My worst month for MPG was January 2005 with a mean temp for the month of -10 C and MPG of 42 MPG in my Prius, my overall MPG average for that year was 49 MPG (June 2004 to May 2005). Last winter your worst month was February with a mean temp of -16 C, we would have to see how someone in Alaska or Canada has done in winter to know how much worse it might get. I also make a lot of short trips driving kids to school and such so that kind of driving also describes me (except I make weekend trips to Sugarloaf to ski most of the winter about a 2 hour drive at about 50 mph). For me there was a 14 % drop in mileage for my worst winter month. If we assume it will be a little worse for you, say 20 % then you would see your MPG drop from 39 to 31 in your coldest month. For the winter as a whole (December and March aren't usually as bad as Januarry and February) I see about an 8 % drop, if you have a 12 % drop that would bring you from 39 to 34 MPG for the winter. I think you would do fine the rest of the year and a block heater would probably help on the morning commute. I just installed a block heater last week and I'll let people know if it helps once winter arrives, but others at Prius chat have claimed it makes a big difference in their MPG especially on short trips in cold weather. Below are links to monthly and seasonal MPG.
by Month (http://www.cleanmpg.com/photos/data/500/prius_mpg_month.jpg)
by season (http://www.cleanmpg.com/photos/data/500/prius_mpg_season.jpg)


Dennis

Once again, thankyou very much to all the contributors on this thread, it's all very helpful!!

One more comment after re-reading Wayne's comments. He is probably right that you will probably not do any better than a regular Camry during the coldest months (January and February) but the other 10 months of the year will be fine, if you have the dealer add the block heater (probably about $100 installed) if it isn't already standard in your area, the cold weather hit won't be as bad, but I think my mileage estimates for winter may have been optimistic, it seems on the RSX the winter hit is close to 30 %, I would expect the Camry would be that much or maybe more. Also check out Greenhybrid and ask this question in the TCH forum, though I imagine nobody has been through a winter in a TCH yet.

Dennis