All my friends know that I am getting a Prius now and they are asking all kinds of questions about it. One they got me on was about the heater. If you can't start the engine until your moving, how do you let it warm up or defrost befor driving it in the winter?

The ignition switch has a "start" position just like normal. On my test drive, I observed that starting the car normally does start the engine. When I shifted into drive the engine stopped, running pure electric. So I believe you can warm it up in park before driving, like normal.<br><br>I wonder if there is a way to keep the engine running to get the coolant up to heater temperature in winter.

So, we might still need to do the good o'fashion "cardboard over the radiator" trick on those cold winter days.

AT initial start, when you put the key in the ignition, the generator spins the motor to approx. 1400 rpm, at which point the gas/oxygen mixture is injected and the engine is started.<br>The gas engine stays on initially until coolant reaches operating temperature and main battery pack at a certain SOC level. After warm-up the THS will begin optimizing for the best combination, and of course you'll have heat for the cold mornings......Priusman

I see, So it knows when its cold.<br>Thanks Priusman

The engine will remain on during initial start up until the two inputs are met: coolant temp and battery SOC. Once these two level are attained the engine shuts off automatically, but the car is still ON. So at rest, the car can actually be on (with the key in the IG switch ON position). And will turn itself on to run the AC for example.....Priusman

From what I understand, both the A/C and heater work off the heat pump - no need for hot water from the engine. The A/C in reverse heats.

Prius doesn't have a heat pump. Heat is by conventional heater core using engine hot water and AC is by engine driven compressor. Heat pumps are expensive and only required for battery EVs.