We managed 29.9 MPGe on a recent trip of 3.4 miles due to the really confusing way the heat works. It was about 30 outside and my wife set the heat to 75. The ICE kicked on, but the battery level kept dropping too, indicating to me that it was trying to heat with both. Naturally it didn't really start blowing until halfway through the trip since nothing was really warm yet.
Is there any way to avoid this wasteful situation where it's using both systems to heat? Is EV Now mode reasonable? I would be OK with it ignoring the battery energy and just using the ICE for the trip, which should at least get 35-40 MPG, but using both seems just ridiculous.
From my standpoint you've got a few options/methods to think about... And as always these can be impacted by what your later travel plans are as well...
1) Leave the heat off. Depending on how long in time your 3 miles are, you're not going to get much anyway.
2) Put it in EV Now mode and be careful with how much heat you ask for as well as how cold it is. And don't ask for defrost. Then you should be able to just suck up a bunch of battery and never start the ICE. You should get a bit of heat before the trip is over.
3) Put it in EV Later and it should suck down battery and gas, but this should be about the fastest way to get heat(though I'd still say you're not going to get a whole heck of a lot depending on actual time involved in this trip). But, at least the ICE will be put to use replenishing the battery it's using for the electric heater as well.
The biggest issue I see is just trying to let the car sort it out itself in Auto. There are plenty of times when it seems just SUPER stupid... Basically it fires up the engine cause for heat because it's reached whatever the degrees inside or out that it's programmed to do that. And THEN it decides to still use the battery basically as much as possible. So... I get like 30MPG out of the gas burner which is essentially just wasting gas, *maybe* providing a little heat, but at the same time it's sucking down the main battery at max rate since it's still getting used for heating and about 90% of the power to the wheels.
So, generally it seems better to either choose EV Now or Later depending on how/when you want to allocate your resources... I only switch to auto at times like when I've been in EV Later and it's already warmed up and we're on a downhill or in town where I'm just creeping around and the ICE will actually shut off again.