What is PUE (ISO/IEC 30134-2)?
PUE, or power usage effectiveness, is a data center efficiency metric equal to total facility energy divided by the energy used by IT equipment. A value of 1.0 would mean every unit of energy reaches the IT load. It was developed by The Green Grid and is standardized internationally as ISO/IEC 30134-2.
What it is
PUE shows how much energy a data center spends on everything other than computing: cooling, power conversion and distribution losses, lighting and support systems. The closer PUE is to 1.0, the less overhead.
ISO/IEC 30134-2 defines how to measure it, including where to place meters and which energy to count, so values are comparable. PUE should be calculated over a period, typically a year, because it varies with load and weather.
PUE does not measure IT efficiency itself, and a site can lower PUE while wasting energy in servers. It is a measure of facility overhead, best read alongside other metrics such as WUE.
Where it is used
Colocation providers, hyperscale and enterprise data centers, and edge sites use PUE to track efficiency, report to customers and investors, and meet reporting rules in some jurisdictions.
It is also used inside mixed-use buildings and campuses that host server rooms, where cooling for IT loads can be a large share of total energy.
How it is measured
Accurate PUE depends on metering at the right points.
- Total facility energy at the utility input
- IT equipment energy at UPS output or PDU level
- Measurement interval and reporting period
- Cooling energy by hall or system for diagnosis
How Aqueduct helps
Aqueduct calculates PUE from measured inputs per hall, continuously, with the cooling faults that move it found and fixed.
- aQ EnergySmart electrical single line from utility input to IT and cooling loads
- PUE per hall, refreshed every 60 seconds, not estimated once a year
- Cooling faults such as simultaneous heating and cooling or failed economizers flagged
- Verified change in PUE after each fix