When running on ICE, does the cabin heating come from the ICE?

Depends on who you asked, prior to the annoucement of the HOLD button for the US model.

There were a few Volt owners & supporters who were downright hostile when it came to this question, believing your only purpose for asking the question was really just to promote the plug-in Prius... since it would come with the HV/EV to preserve battery and allow you to take advantage for heating.

I suspect HOLD does the same thing.

And my guess for the reason the US market didn't get the HOLD button right away was GM's push to have Volt identified as an EV. Being able to switch to HV driving would obviously tarnish that.

 

Yes, they use waste heat from the ICE to warm the cabin. That only makes sense because the ICE is so "wasteful". In the current config (with a new temp in the works), if it is below 26F then the ICE will run for 2-3 minutes to heat the cabin extra quick without using excessive electricity. If you are moving at the time it burns 0.07 gals of gas and not moving it burns 0.03 gals of gas during those couple minutes.

Keeping the climate settings on 'comfort' (vs eco) also keeps the coolant loop on thru the ICE so it stays above 115F for a long time which is where the ICE would kick back on a for a couple minutes. I have a detailed post on this on gm-volt.com.

 

I heard it was emissions related. Allowing consumers to change emissions profile with a button got some people's ire up.

 

You are very welcome. Here you go:
COMFORT setting limiting "Engine Running due to low temperature" ERDTLT

 

And I believe Toyota didn't offer the EV button on the gen2 because they thought Americans were too dumb to read up on it in the manual, and didn't want to waste dealers' time on complaints on the EV not working when it is doing what it was designed to do.

The more likely reason for both companies.