White space optimization, and power and cooling audits can lead to the determination of the Power Usage Effectiveness (PUE) audit and calculation.  The calculation of the PUE involves determination of infrastructure elements inside the Data Centre, and not just power and cooling systems.  Together, these four audits provide the most comprehensive information and improvement plan on the Data Centre.

There are established best practices in the calculation of PUE in the Data Centre that are followed by CNS.  PUE measurements are important to know the energy efficiency of not just the structural components of the Data Centre, but the effectiveness of its integrated design.  PUE measurements need to be made throughout the year, to know the impact of varying loads and seasonal changes on the efficiency of the Data Centre.