ALL THE ABOVE:Any highway driving produces drag, just stick you hand out the window at 55 mph. Air drag goes up with the square of speed (or something like that) not linearly. Speed can be less noticeable with ICE because it has a sweet spot that is designed in usually between 2,000 and 4,000 rpm. Electric motors don't have that being more efficient at low rpm with decreasing efficiency as it rises. A/C is more efficient than heating. Fans don't use a lot of electricity (compared to a heating element). Greater acceleration takes more energy than less even though it might be required for a less amount of time. Lubrication is thicker at lower temperatures so requires more energy to overcome the increased friction. All factors to range (there are more).