Warming up the car in winter

I agree with all your points but, I was speaking of airflow out the windshield vent for purposes of severe fogging. Only the defrost button puts out a real quantity of air, but, that starts the ICE.

 

That's what I said in my first two posts in this thread, no ICE, no heat. You can get heat from the seat heaters, but that doesn't help defrosting the windshield.

 

Agree on all points and I have done this many times. However traveling back from the mountain base with my spouse. Which means NO windows open, because one gets a draft. So double breath inside, closed windows, quite cold outside all = fogging up of the windshield. Only the defrost button would cure that problem, it had sufficient volume of air to clear the problem.

 

No, it doesn't .

 

My first post on page 1

In a nutshell, no ICE, no heat. The regular GenIII is another story. It has a heating element in the HVAC system.​

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My second post on page 1.

If the ICE didn't run at all, you won't get any heat. The ICE is the only source for heat in a PIP. ​

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for me, i have noticed the ice will eventually shut off, even with my heat still on....

 

Right. If the coolant temp isn't too low, you can still get heat w/the ICE off.

 

yes, the ice shuts off after it reaches operating temp and comes back on after the coolant temp drops below a threshold. the op is stating heat without ice ever coming on. i think.

 

k, i just wanted to throw that in there..haha, i don't know crap, this car confuses the heck out of me but i LOVE it!!!

 

Coolant temperature is not the only threshold with the plug-in model. It's quite a bit lower than the 114°F threshold we've been used to with the regular model. I was finally able to confirm that discovery late at night.

It went all the way down to 94°F before the engine fired up again.

Think about that for a moment. If it were 94°F outside, would you feel warm? We know that Toyota found a way to heat up the emission system faster with this model too. So, why not?

I went out to run an errand. I pushed the defrost button with the temp already set at "LO". The engine fired up anyway. Fortunately, I had just come to a lonely stop. So, I shut the defrost off, then powered down the Prius and back up again. Using the head & foot option instead, no engine. That continued for about 1.5 mile until finally needed heat. So, I bumped the temperature to "HI" and allowed the warm-up cycle to run its course.

When the engine shut off, I set the temperature to "65" and lowered the blower to 2 bars. The interior stayed comfortable and the windshield clear the rest of the drive. The engine did the usual cycling, starting up at 114°F and shutting off at 130°F. After a few cycles, I noticed a drop below 114°F. That peaked my interest. Without any interruption to heat, it went all the way down to 94°F before the engine started up.

My theory is some other component was warm at that point, no longer immediately dependent upon coolant to sustain anymore.

Long story short, setting the heater to "65" and the blower to 2 bars following warm-up appears to be a simple & efficient choice when you're driving in sub-freezing temperatures.

 

why some other component? isn't 94 degree cooland warm enought to heat air to 65?

 

to answer the OPs revised wording: To turn on the car, means to put it in ready. If you put the car in ready all that will happen is 15 minutes of empty mpg bars, if you sit in the car during this time, your body heat may warm up the interior.

 

Now, that's the best post in this whole thread.

 

My past experience exactly. I consider it a serious design error.

 

To define problem, NO air comes out of windshield vent under those conditions, hence, fogging occurs, under certain conditions. Again a serious design fault, even dangerous! I really expect to see some accidents happening to people that are not aware of how fast the windshield can fog up.

 

Emissions are a major priority. A short burst from the engine likely works out better overall, especially when you consider how warmth spreads given time but can be lost given too much. We know that use of the battery itself results in heat too.

 

Why would you expect OFF to deliver a flow of air?

 

Actually, it appears that the OP has more than one Prius. By now, he, they should know what happens when one turns "ON" a Prius for 15 minutes and does nothing else. The question is illogical.

 

I was addressing Adams situation, which was identical to mine. A serious design error. To answer your question, YES, I would expect some air to the windshield, without having to use the defrost button. Cool or warm does not matter, altho cool seems to work better. EVERY car I have ever had allowed this. If you have ever driven in Hawaii, you would have noticed that the windshield can fog up immediately! The natives cure for that is to drive with the window open in the morning. I know you drive with the window cracked open, and that's fine, but that's a work-a-round. I normally also do the same. To the uninitiated, this is a accident waiting to happen.