PUE · Power Usage Effectiveness
Annual total facility energy divided by IT equipment energy (ISO/IEC 30134-2). 1.0 is the floor; an instantaneous or design-point PUE is a weaker claim, so ask which one a vendor quotes.
Annual total facility energy divided by IT equipment energy, measured over a full year per ISO/IEC 30134-2; the headline data-center efficiency ratio, lower is better.
Also written as: Power Usage Effectiveness
Current numbers
≥500 kWEU EED data-center reporting threshold (~31 data points incl. PUE/WUE/ERF/REF; due 15 May annually)
1.36Uptime 2026 survey: capacity-weighted PUE
1.52Uptime Institute 2026 survey annualized PUE, per-facility respondent mean; capacity-weighted, the same survey gives 1.36 (Chapter 15.1)