The U.S. government’s Data Center Consolidation Initiative (DCOI) requires all Federal agencies and departments to achieve and maintain a PUE of ≤1.5 for existing “tiered” data centers. New data centers must design and maintain a PUE of ≤1.4.

This paper provides an explanation of the PUE metric, listsfactors impacting data center efficiency measurements, and describes ways to improve PUE by reducing energy consumption of power and cooling systems supporting the IT.