A facility drawing 1,500,000 kWh against 1,000,000 kWh of IT load lands on a PUE of exactly 1.5 — and the classification rule's strict less-than comparison puts it in the band below where a casual reading might expect.
| Total facility energy (measurement period) | 1,500,000 kWh |
| IT equipment energy (same period) | 1,000,000 kWh |
| Electricity rate | $0.12 / kWh |
The classification uses a strict less-than comparison at each band boundary: PUE < 1.2 is 'world-class', PUE < 1.5 is 'efficient', PUE < 2.0 is 'moderate', and so on. A PUE of exactly 1.5 does not satisfy 'PUE < 1.5', so it falls through to the next band down.
| Check | Requirement | Actual | Status |
|---|---|---|---|
| PUE | n/a (this is the result) | 1.50 | ✓ PASS |
| DCiE | n/a (this is the result) | 66.67% | ✓ PASS |
| Efficiency band classification | n/a (informational) | Moderate (PUE 1.5–2.0) | ✓ PASS |
Key insight: Efficiency-band boundaries in any classification scheme need an explicit rule for values that land exactly on the boundary — this calculator treats a PUE of exactly 1.5 as belonging to the band below the 'efficient' threshold, since the 'efficient' band is defined as PUE < 1.5, not PUE ≤ 1.5. A facility this close to a band boundary is a reminder that small operational efficiency gains (a few percent off total facility energy) can be the difference between two full classification bands.
Every input in this example is editable in the live calculator — free, no signup.
Open Data Center PUE calculator →No — ISO/IEC 30134-2 standardizes the PUE metric itself and its measurement methodology, but the specific efficiency bands (world-class, efficient, moderate, poor, and so on) come from The Green Grid's widely-cited 2007 white paper, an informal industry reference scale rather than a formally mandated classification within the ISO/IEC standard itself.
Common levers include raising chilled-water or supply-air temperatures to reduce cooling energy, using free/economizer cooling during favorable outdoor conditions, improving UPS and power-distribution efficiency, and better hot-aisle/cold-aisle containment to reduce the fan and cooling energy needed per unit of IT load — all of which reduce the 'overhead' energy in the numerator without touching the IT equipment energy in the denominator.