It doesn't get better gas mileage. Think about it. He charges the batteries from his outlet. He's not get the extra miles from the gasoline, he's getting them from the natural gas, coal, protons, etc. that is energizing his house. Most certainly at less efficiency.
By this logic one could push their car to work, drive it home, and thus double their mileage.
"He's not get the extra miles from the gasoline, he's getting them from the natural gas, coal, protons, etc. that is energizing his house. Most certainly at less efficiency."
The difference environmentally is that oil is dirtier, and the difference economically is that it's a heck of a lot cheaper. Why be cynical about this? WOuldn't you want to save money?