Design PUE

Design PUE is the power usage effectiveness a data center is engineered to reach at full load, not the PUE it measures in operation. Operators publish design values such as 1.2 to 1.3 for air-cooled colocation and 1.1 to 1.15 for liquid-cooled or hyperscale halls. The two numbers often differ: a facility only partly filled runs below design efficiency because cooling and electrical losses are fixed, so early-year measured PUE can sit 0.1 to 0.3 above target. When comparing sites, check whether a quoted PUE is design or measured, annual or best-month, and at what load.