PUE for Data Centers

PUE Peak

Power Usage Effectiveness (PUE) is a metric used to verify and improve energy efficiency in data center operations.

The PUE evaluates the performance of the data center by calculating the ratio between the energy it uses as a whole and that used only by IT equipment.

The PUE value is defined as the ratio of two numbers: the data center input power versus the IT load power supply.


The total power of the facility includes all the energy of the IT equipment as described in the previous point plus everything that supports the IT equipment that uses energy, such as:

  •  Power Components, including UPS systems, panels, generators, power distribution units (PDUs), batteries, and distribution losses external to IT equipment
  • Cooling system components, such as chillers, cooling towers (not present in our case), pumps, air handling units (AHU), computer room air conditioning units (CRAC), and direct expansion air (DX), heat pumps, etc.
  • Other loads of miscellaneous components, such as data centre lighting

The IT Equipment Energy includes the energy associated with all IT equipment (for example, computing, storage, and networking equipment) along with additional equipment (for example, switches, monitors, and workstations/laptops used to monitor or otherwise control the data center).

Seasonal PUE

The calculation of the seasonal PUE is performed considering the variation of the climatic conditions (external temperature) throughout the year which corresponds to variations in the thermal load of the building and consequently variation of the electrical load and in this, it differs from the previous calculation of the Peak PUE

Regard the daily hourly load profile (relative to each month), usually for a Data Center simulation must be performed.