Fuel Economy and Daycare

I think that's probably a good idea. Leaving the car on should help and avoid an unnecessary second warm up cycle in the morning. Shutting the car off will mean the warm coolant will be pumped back into the thermos, and the engine allowed to cool down rapidly. Leaving it on, even though the engine is off, and everythings running from battery power, should help. I do that all the time when i go to the market for a quick errand, and it has helped my fuel economy.

 

It would just be nice if we could find a way to lock it while it's on..

 

you could try it both ways as the consumption screen should give you a pretty clear indication how much both way's affect your mileage. The first 5 minutes is the killer of mileage so keeping it running might just help. But in the winter you will suffer along with all other vehicles out there not just Prius. Just your hit will be less than theirs. You a candidate for a block heater with this short trip, as starting off almost at nomal temp will help your mileage.

 

I've found a way... use the physical key.

 

If you park in a garage, a block heater may not be necessary. My garage has insulated doors, so it doesn't get all that cold. If your situation is similiar, I'm not sure you'd see much benefit.

 

I am not at all sure that is true. I live in a very moderate climate. We are now in the high 40's low 50's in the morning. I have my car in a insulated non heated garage and while the temp is higher than outside it is still cold. There is not a huge improvement in the temp rise after the thermos dump after sitting all night. I have the ScanGage to monitor engine temps and with out the block heater it is starting in the 70's and rises slowly to full hybrid temps. With the block heater the temp starts at 137 drops to 120 or so then rises with in 1-2 Min to full hybrid temps. With a combination of the block heater and a new rout that is more pulse and glide friendly my last two tanks have been around 60 mpg. Looking back on my data from last fall and winter I was in the low 50's unless the temps dropped to the 30's for a period of time. Your temperatures are much more extreme. Yes you do better than I in the summer (other than having to use air and that is uncommon for us unless it gets into the high 80's) our winter temps are also moderate. I would think you would benefit more with a block heater than I do. I will grant you the power I use is cleaner being hydro for the most part, but it does not take much more power with a timer to preheat your car and you will have the added benefit of keeping your self and the kids warmer sooner.