Yes, it makes a difference but not enough to make fuel consumption a serious consideration. In fact, you would probably be hard pressed to accurately measure the difference.
Where you will notice it is inside in the living space. On the surface it looks like you are adding 6.25% to the width and that doesn't seem substantial but reality is once you account for wall thickness and cabinets and other protrusions into the space, the actual open space will increase by more like 10-15% and that's what you really assess in terms of living space.