I actually asked Kia about
I actually asked Kia about this, and this was their reply: “ Kia’s plug-in vehicles – including Sorento PHEV, EV6, and Niro EV and PHEV - use a separate high-voltage battery heating and cooling circuit that is specifically engineered to manage the high-voltage battery’s temperature. For the PHEVs, considering their smaller battery size versus our EVs, the size of the battery heating/cooling circuit is unlikely to provide sufficient heat needed to properly heat the car’s cabin. Therefore, for PHEVs, heat generated from the I.C.E. is used to heat the cabin.” So, basically, Kia is telling us that for PHEVs, they don’t use the battery for cabin heat because of the size of their batteries/the efficiency of doing so was not adequate or “not likely to provide sufficient heat…”. My 2017 Chevy VOlt, which has about 5 additional kWh of battery capacity, used a resistive electric heater, but could also utilize heat from the gas engine, when in use. I also think that is a better design, but I do understand Kia’s logic here: their batteries are “just” big enough to provide the intended functionality (i.e. around 32 miles of range in their SUVs) and they would 1. use up to about 30% of battery capacity for heating if they used the battery for heat (resistive heat mind you, not a heat pump) 2. their vehicles would be more expensive, with the addition of an electrical heating system and a larger battery to offset (and perhaps more robust battery cooling apparatus to deal with the additional load, heat pump or otherwise). 3. since you’re going to get less range in cold weather (especially extreme cold weather) it increases the likelihood of needing the gas engine anyway, so the logic of adding more expense and weight to the vehicle sort of holds up. My suggestion: the Sorento PHEV “idles” the engine for heat; you might want to experiment with just using the heat vs. putting the car into HEV or Sport mode at the start of your drive, depending on the distance of your drive, and then switching to EV mode after the engine has warmed up and seeing if that residual heat plus seat heaters/steering wheel are adequate to get you to your destination. That, or consider getting a full EV or a plug-in hybrid vehicle with a larger battery the next time you are in the market… as I am afraid Kia’s design may not be optimal for those trying to best reduce gasoline use and who live in regions where lengthy period of sub freezing temperatures are the norm. I realize, that last part isn’t much comfort, but hopefully you might at least find some better results/get better efficiency “playing with” the modes to warm up your engine faster than just idling it when you turn on the heat.