comparison - “energy saving” vs. “energy savings”

Assume that A and B are two systems. For example A consumes 3unit and B consumes 4unit of the energy. Now we know to A saves 0.25% in energy consumption than B.I want to draw a diagram and want to type on the y axis. I would like to which of these is correct:

1. . . . the energy saving ratio of A to B . . .


2. . . . the energy saving ratio of A than B . . .


3. . . . the energy savings ratio of A to B . . .


4. . . . the energy savings ratio of A than B . . .


5. . . .. or?