• Home
  • >
  • Blog
  • >
  • Everything You Wanted to Know About PUE

Everything You Wanted to Know About PUE

Tom Hassan

Digital Marketing Executive at Node4

Power Usage Effectiveness (PUE) is the measure of how efficiently a Data Centre uses energy.

How is PUE calculated?

In essence, the PUE is the ratio of the energy used by the Data Centre against the energy used by the Data Centre to deliver its services. It looks like this:

 

Don't be fooled by its simplicity; this ratio is a big deal!

It is the most commonly used metric for reporting the energy efficiency of Data Centres. Moreover, PUE drives competition as Data Centres report lower and lower results.

Why is PUE Important?

PUE is a tool that Data Centre owners can use to measure how well the infrastructure is working. It also is a useful tool for identifying areas of improvement—the lower the PUE rating the more efficient the Data Centre.

The PUE is higher for more inefficient Data Centres; facilities that require more power will more than likely have higher operating cost.

PUE Level of Efficiency
3.0 Very Inefficient
2.5 Inefficient
2.0 Average
1.5 Efficient
1.2 Very Efficient

(Source: http://www.42u.com/measurement/pue-dcie.htm)

Is PUE a dynamic number?

The PUE will change as the load on the Data Centre changes, on both the overhead and IT equipment sides. Moreover, seasonal changes outside can affect a Data Centre’s PUE, too.

However, that doesn’t mean that the PUE is a useless number. It is a useful indicator of the effectiveness of the whole Data Centre, and can be used to highlight areas that need changing and improving.