Winter MPG drop in my PHEV and what I learned

[MoMo]

Last winter I was really confused by how low my PHEV's MPG dropped. I was mostly driving in EV mode, but the numbers didn't add up. Then I noticed something: when the heat was on, the gas engine would run just to warm the cabin. The car counted fuel use, but not mileage. Even sitting still, the MPG would drop fast...looking back, I now know those winter MPG readings were completely misleading

 

[gunnar4603]

Last winter I was really confused by how low my PHEV's MPG dropped. I was mostly driving in EV mode, but the numbers didn't add up. Then I noticed something: when the heat was on, the gas engine would run just to warm the cabin. The car counted fuel use, but not mileage. Even sitting still, the MPG would drop fast...looking back, I now know those winter MPG readings were completely misleading

Yeah common issue, when the heater runs the gas engine just to warm the cabin , the fuel used doesn't add any mileage, so the mpg numbers drop even if you're mostly in EV mode. It can make winter MPG look way worse than it really is

 

[NoGasLOL]

Last winter I was really confused by how low my PHEV's MPG dropped. I was mostly driving in EV mode, but the numbers didn't add up. Then I noticed something: when the heat was on, the gas engine would run just to warm the cabin. The car counted fuel use, but not mileage. Even sitting still, the MPG would drop fast...looking back, I now know those winter MPG readings were completely misleading

my advice is to prioritize the heated seats and steering wheel over the main cabin heat. They use way less energy and will keep you just as warm without needing the gas engine

 

[Karenn]

PHEV MPG ratings in winter are basically a scam, manufacturers know cabin heat forces the gas engine to run, tanking efficiency, yet they market those inflated numbers as if they apply year-round.

 

[MoMo]

Yeah common issue, when the heater runs the gas engine just to warm the cabin , the fuel used doesn't add any mileage, so the mpg numbers drop even if you're mostly in EV mode. It can make winter MPG look way worse than it really is

It really skews the numbers and makes you think the car's less efficient than it is... I wsh manufacturers were clearer about how heating affects MPG so owners aren't caught off guard every winter

 

[MoMo]

PHEV MPG ratings in winter are basically a scam, manufacturers know cabin heat forces the gas engine to run, tanking efficiency, yet they market those inflated numbers as if they apply year-round.

It feels misleading when they promote best-case numbers that only happen in mild weather. Real-world winter performance should be part of the official rating so buyers know what to actually expect before they commit

 

[gunnar4603]

It really skews the numbers and makes you think the car's less efficient than it is... I wsh manufacturers were clearer about how heating affects MPG so owners aren't caught off guard every winter

Totally agree, winter heating definitely hits efficiency more than most realize. Hope manufacturers find a way to could include that info in the mpg estimates or manuals to set better expectations

 

[Route 55]

@MoMo Damn... I feel you. Winter really throws off the MPG numbers, so thank goodness we're still a long way from there. Using seat and steering wheel heat instead of full cabin heat can save a ton of fuel without freezing.

 

[Alan]

@MoMo Yep, exactly. Winter MPG on PHEVs can be super misleading. The gas engine running just to heat the cabin skews the numbers, even when mostly driving in EV mode. Using heated seats and steering wheel instead of full cabin heat is a smart way to stay warm without wasting fuel.