Gas on to heat car - does it defeat the purpose

I read that in order to use the heat in the car the gas engine needs to run. So if it is cold out and I am driving 10 miles to a destination is the engine on the entire time because I am running the heater? Does that defeat the purpose of the plug in?
Help me to understand?

I would consider pre-heating the seats and running the 10 miles on seat heaters, but that is an uninformed poster who does not own a PiP.

and what do you do if the windshield has frost on it?

Scrape it off? I'm way too impatient to let my car run for as long as it would take to melt frost on the windows.

I knew you would say that......up here, when you scrap the windshield, it just refreezes over

There are electric heating elements that suppliment the heater core.

yeah, that's the rumor going around, need facts tho

Heat from the engine does not defeat the purpose of having a plug.

You still get an extremely efficient system even when the engine runs. Just look at what happens when you accelerate onto a highway when the system is cold. The result is MPG above 50 during warmup. That's a fantastic worst case scenario.

Heat comes from warmed coolant. Once warm, the engine will shut off. It will remain that way until the coolant temperature drops below a threshold (which is 114°F in ECO mode and 145°F in Normal & Power). The engine will then start up and run. It doesn't take long for that threshold to be reached at the engine shut off again.

So while driving in EV, the engine will cycle on & off. That's actually the same as what happens with the regular model Prius, only you have much more power available when driving with the engine off.

For me, with heavy commute congestion caused by snow, I remember being shut in hopelessly slow traffic watching the engine start up every 8 minutes. That seems like a surprisingly long time to have the heater running without the engine providing any warmth to the coolant... until you witness it firsthand and think about how Prius was designed specifically with heat creation & retention as a priority. Remember, heat is also needed for cleansing emissions. So generating it quickly is very important.

You have to define what your purpose is.
If it is to save CO2 emmissions and you live in a state that makes heavy use of coal, then no, it doesn't.
If your purpose is to reduce the need for foreign oil (for national security or financial reasons) yes it does.
All in all, it is a design choice of the car. Since it has an ICE, and the ICE is very good at throwing off waste heat, it is a fairly efficient way to heat the car. As long as you don't care about burning gas.

Part number is 87710-12020 quick heater. It comes up on online searches for Corollas, but the part number came out of a Prius parts manual. It sits atop the heater core. The car also has a water jacketed exhaust system, so the exhaust heats the coolant faster.

I ran into this same question with the Gen. II. This is my opinion about it:

If you need the heat, use the heat, If you need the AC, use the AC. If you work at it, you can find edge cases where anything is not absolutely thrifty. You are not a monk, sworn to hairshirts & suffering for the glory of God, or Akio Toyoda, or something. The important thing is that on the whole it is one of the best and thriftiest cars around. Defrost those windows. Heat those seats. You will make it back later.

So I am not sure my question was answered. If I were to purchase the plug in prius on a cold day the engine is going to run on gas until the heater has waremed up the car correct?
Then I will not be running on 100% battery on short trips on cold days.

Just wondering: is it possible to delay (or shut out) the EV portion with PIP?

If you set the climate control to a temperature that is high enough to call for heat, then the engine will start and warm up. If you want to avoid this, you can follow the advice from post #2 which is to set the climate control so it doesn't call for heat and use the seat warmers.

Yes, there is an EV-HV Mode button which toggles between the modes.

Since the purpose of a plug-in hybrid is to significantly reduce emissions & consumption, driving 100% battery isn't high up on the priority list anyway.

The engine will run for a few minutes. For me with the 2010, jumping on the highway just 3 blocks from house, the heater is pumping out warmth before the first 5-minute segment. With the PHV, you'll be getting boost from the battery too. So hopefully, less heat will lost through the tailpipe.

We'll find out soon enough... with me here in Minnesota.

Last night I found that if in ECO mode, and calling for heat on a 59F degree night, the ICE would not start. It would only start ICE when i took OUT OF ECO(Normal mode)

I never had really used anything but ECO and tried POWER once or twice, so for saving power ECO does help to keep ICE off when calling for heat. The defroster can blow hard, and i think it might be slightly warmed from an elec element to defrost even without running ICE on moderately cool days. And using heated seats to help keep warm.

But remember the motor warms quickly, and you can get good heat after a short run of ICE and then go back to EV mode when cabin is warmed and continue using heated seats.

Dan

the answer to your question: no, you cannot drive strictly on EV on your commute if you want heat.

that being said, i have always done my 15 mile r/t commute in winter clothes to avoid running the heat and save gas in all my pri, with no heated seats, so this should be a breeze. the big prolem is when frost forms on the inside of the windshield.

So then is there a benefit to pip?

it's not cold where you are in the summer, think of the overall benefit of the PIP vs non PIP