Here’s a neat little calculator from 42U. In a single page, with the input of a few figures which are easily obtained, you can get a good overview of the savings achievable by aiming for a specific Power Usage Effectiveness (PUE). The calculator asks for your existing PUE rating if known, and you can then adjust the target PUE. Input the cost of your electricity and your IT load in Kilowatts and off you go.
The resulting calculations tell you just how much money and CO2 you will save in the short and long term if you achieve your selected PUE goal (below).
If you are new to the world of Data Center Efficiency and energy saving, this is a great introduction. It doesn’t go into too much detail and there are some handy notes on the same page which will assist in the learning curve too. There’s even a video if you can’t be bothered to read – perfect for a Friday afternoon!