AI Vocabulary · 02 AI Infrastructure

What is PUE (Power Usage Effectiveness)?

The standard efficiency figure for data centres: total electricity of the site divided by the electricity that reaches the IT equipment.

Intermediate

PUE stands for Power Usage Effectiveness. It divides all the electricity a data centre draws by the share that actually reaches servers, storage and network. Everything above 1.0 is overhead: cooling, power conversion, lighting. A PUE of 1.5 means that for every kWh of computing, another half kWh goes into running the building.

According to the Uptime Institute's global operator survey, the average PUE has barely moved for six years and stood at 1.54 in 2025. New and large sites do better, and the best sites of hyperscalers reach 1.1 to 1.2, according to the International Energy Agency.

Why it matters for you

PUE tells you how much electricity a provider wastes around the chips. It says nothing about the carbon in that electricity, the water used for cooling or whether the chips sit idle. A low PUE is a good sign and only one part of the picture.

Own it

When you compare cloud or colocation providers, ask for the annual PUE of the specific site, alongside WUE and the share of clean electricity. Treat figures without a site and a year as marketing.

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