1. A method to calculate energy efficiency of information technology equipment a. The method of claim 1 wherein said method is used to calculate an absolute rating of energy efficiency of information technology equipment. b. The method of claim 1 wherein said method is used to calculate a normalized rating of energy efficiency of information technology equipment over time. c. The method of claim 1 wherein said method is used to generated a normalized ratings graph for information technology equipment that shows the expected rating of such equipment over time and in the future. d. The method of claim 1 wherein said method is used to give purchasing guidance based on said energy efficiency ratings so that equipment purchasing decisions can include performance per energy usage. e. The method of claim 1 wherein said method is used to provide a common metric and measure and basis for additional comparisons of equipment performance per energy consumed.