Mpg drop in winter.
 

I guess I would be right in saying that a hybrid loses more mpg due to cold weather than a car with ice only. Living in this cold climate I’m probably not getting as big a gain from my last car ice as I hoped I would. Never factored this variable in when I bought my Niro which was getting 4.5l/100k now i’m Getting 6l/100k which is still decent I know.

I drive an all electric leaf and I am seeing around a 20% drop in range and economy.

I think the mpg drop is very similar in hybrids and gasoline only vehicles. Hybrid's gas mileage is just so much higher that the numerical value drop makes it seem like its larger.

I saw about a 20% decrease this morning when I turned on the heater in the Volt

Not sure how cold it is where you are, but that's pretty typical. There are a lot of factors that reduce economy in cold weather:
- cold engine
- cold transmission and differentials
- higher air density increasing aero drag
- higher air density increasing engine pumping losses.
- spinning on slick surfaces, or slow traffic on slick surfaces

A block heater helps quite a lot for shorter trips. Grill blocks will help a bit too.

Cold weather, ICE vs. HEV

HEV may take a bigger percentage hit due to:

1) the inherent loss of efficiency the ICE experiences in cold weather
2) HVAC heating demand forces ICE to run when it otherwise wouldn't
3) when hybrid batteries are cold (NiMH < 50°F), the battery utilization is seriously throttled thus reducing the hybrid efficiency, primarily in regenerative braking.

I don't have NiMH or internal combustion engine in my car and see a pretty dramatic drop in range and economy.

Which is completely irrelevant because the OP is asking about HYBRIDS.

Thanks for chiming in though.

I'm just saying the economy loss we see isn't all due to the internal combustion engine or battery being cold.
For me it takes more power to maintain speed when cold.
So cold tires, cold transaxle oil and increased air density would be shared between gas, hybrid and pure electric.

Hybrids lose mileage in cold weather because the IC engine has to run more often to keep the emission control components warm enough to work properly. There are LOTS of postings over at priuschat.com about this.

Bill the Engineer