 Using the heater will take away from the battery. I will get a good 60 miles with the heater running. When I want to see that i'm doing better on mileage, i turn off the heater. I use regeneration stage 1 and gain some mileage. When i am in traffic and is not accelerating, i use no battery power. The only other things using the high voltage battery are the AC and heater. If i think that i need more time on the battery as i drive around town, i slow down. That's why this car give more miles in the city than on the highway.My only issue at this time is the capacity of the battery. I will buy a car with better battery capacity soon.