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Discussion Starter #1
I read that the 2019 will now use the ICE to generate heat instead of "exhausting the battery first". Does anyone know the details on what this means? I bought my 2018 at the start of the summer and now that the colder weather is upon us I'm curious to see how the Volts heating system works. I understand ICE heating well, but not the electric heating in the Volt. Is the 2019's behavior preferred / better?
 

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I believe this is a setting for the 2019 Volt. There is a setting on the 2019 that will use electric only until -14 F, just like our 2016 Volt where the setting for winter, which the owner can input, will not start the gas engine until 14 F, the other setting is 35 F or so.
 

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You'll find many strong opinions about burning gas for heat: the dreaded ERDTT. It is at its most offensive when after your ICE has been turning itself on and off, you arrive at home with charge remaining in your battery.
 

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The issue is not which source of heat (electric vs gas engine) provides better warmth. The issue is preventing the engine from running simply because the weather is cold when you start out or the temperature drops while you are underway.

ERDTT (Engine Running Due To Temperature) will start the engine when the outside temperature reaches a designated low level, and this can be a pain when you’re driving within battery range and don’t want the engine to turn on simply because it’s cold outside. If you’re driving home on battery power and the outdoor temperature drops, for example, the engine may turn on and start running when you’re only a few blocks from home simply because it got cold outside. The manual describes how the driver can select a higher or lower outside temperature option for when ERDTT will engage.

The 2019 Volt options include setting this trigger temperature point lower than allowed for previous models, thus increasing the opportunity to reach your destination in cold weather without having the engine run.

Some users, including those who don’t precondition the car, don’t mind the engine running if it provides cabin warmth without draining the battery by using electric heat. A warm cabin, however, does not prevent the engine from starting when the outside temperature drops far enough to trigger an ERDTT episode.
 

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ERDTT can be annoying if you are only traveling a short distance. Talking to my Volt "Yes, I know it's effn cold out, that's why I preconditioned you before I started on this short grocery run. Running the ICE for 2 minutes isn't going to help."

Although I have rarely encountered ERDTT here in Maryland I have started out on battery only to have the outside air temperature drop to 15F less than a mile from my destination and the ICE starts. It would be helpful to set the threshold temperature low enough that I would never have ERDTT.

If you change the setting for Engine Assist Heat from On to Deferred (there is no Off setting), the change does not take affect until the next time you start the Volt.
 

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All Volts, 1st and 2nd gen, will use waste heat from the ICE to heat the cabin. Obviously, it only works when the ICE is running.

The only 2019 change to the ICE is allowing the ERDTT setting to be lowered even more than before to -14 F.

Maybe I'm a PNW wuss, but if it's below 15 F outside, yes please, burn some gas to keep me warm!!!
 

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To clarify it was this statement in the 2019 review that I was interested in:

"And the gasoline engine now turns on to add heat to the cabin, instead of exhausting the electric battery pack"

https://gm-volt.com/2018/09/27/2019-chevrolet-volt-review/
Never trust a review to contain factual information. The reviewer did the best that they could with limited time in the driver's seat.

The Volt has always had a standard feature called Engine Assist Heat. Engine Assist Heat only operates when the Volt is running in Normal, Sport Mode or possibly in Mountain Mode. When the Volt is in Hold Mode the ICE is already running, at least most of the time, so Engine Assist Heat would not apply. There is a separate, related, setting for Engine Assist Heat (when) Plugged In that can be set to "Off". This is important consideration if you park your Volt inside a garage, especially if the garage is attached to your home. You definitely want to set Engine Assist Heat Plugged In to "Off" if you normally park your Volt inside a garage to avoid the potential build up of deadly carbon monoxide fumes while the ICE is running during the Volt's 10 or 20 minute preconditioning cycle. Of course if you park your Volt outside you may want the ICE to start during preconditioning to warm the cabin faster.

Engine Assist Heat is designed to use a small amount of gasoline to heat the cabin for the comfort of the passengers is cold weather. When Engine Assist Heat is active the message "Engine Running Due To Temperature", (ERDTT) will briefly appear on the driver information console. The ICE will start and will continue to run, even when the Volt is stopped at a traffic signal, until the engine coolant temperature reaches ~160F. After that the ICE will start as needed to keep the engine coolant between 120F and 140F so that there is sufficient waste heat to warm the air going through the cabin heat exchanger. This strategy works well, conserves the Volt's traction battery charge for propulsion instead of generating cabin heat. The Volt will continue to use some of the battery charge to warm the traction battery as required. Engine Assist Heat only heats the passenger cabin.

You can't turn Engine Assist Heat completely off but you can set it from "On" to "Deferred" In the standard "On" setting Engine Assist Heat will start the ICE when the outside air temperature reaches 35F (1.6C) or lower. In recognition that sometimes the driver will not want Engine Assist Heat to start the ICE, when set to "Deferred", the ICE will not start until the outside temperature drops to 15F (-9.4C) or below. In the 2019 Volt this has been changed to allow for deferring engine assist cabin heating until the outside temperature drops to -14F (-25.5C) or below. (I don't know if the new -14F (-25.5C) deferred setting replaces the older 15F (-9.4C) deferred temperature setting or adds a second lower temperature deferred setting.)
 

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Discussion Starter #9
Thanks jcanoe. I have my heating assist set to deferred despite the fact it's parked outside. Since I leave it plugged in I would prefer to draw on the house electricity to precondition the vehicle.
 

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Thanks jcanoe. I have my heating assist set to deferred despite the fact it's parked outside. Since I leave it plugged in I would prefer to draw on the house electricity to precondition the vehicle.
Then you should also set the related setting, Engine Assist Heat Plugged In, to "Off". Otherwise, if you only set Engine Assist Heat to "Deferred", if the temperature were to drop below 15F, the ICE would start even when your Volt was plugged in while preconditioning.
 

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Discussion Starter #11
Then you should also set the related setting, Engine Assist Heat Plugged In, to "Off". Otherwise, if you only set Engine Assist Heat to "Deferred", if the temperature were to drop below 15F, the ICE would start even when your Volt was plugged in while preconditioning.
Done, thanks for the recommendation.
 
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