Data Center Energy Efficiency: PUE, Explained (+ Calculator)

One number tells you how efficient a data center is: PUE. Here's what it means, what good looks like — Google runs 1.09 while the industry averages 1.54 — and a calculator to work out your own.

What PUE means

Power Usage Effectiveness = total facility power ÷ IT equipment power. A PUE of 1.0 would mean every watt goes to computing; everything above 1.0 is overhead — mostly cooling, plus power-conversion losses and lighting. A facility running at PUE 1.5 burns half a watt of overhead for every watt of compute.

Google reports a 2025 fleet-wide average PUE of 1.09; the Uptime Institute's 2025 Global Data Center Survey puts the industry average at 1.54 — meaning the best fleets run about 83% less overhead energy than the average facility.

PUE calculator

How facilities push PUE down

• Free cooling — using cold outside air instead of chillers wherever the climate allows.
• Hot/cold aisle containment — stopping chilled and exhaust air from mixing.
• Raising temperatures — modern hardware runs safely warmer than old habits assumed; every degree saves chiller energy.
• Liquid cooling — pumping coolant beats pushing air, especially at AI densities.
• Efficient power chains — fewer conversion steps between the grid and the chip.

Cooling guide →Power →