Glossary

Critical IT Load

Also known as: IT load, critical load

The amount of power, measured in kilowatts or megawatts, that is actually delivered to IT equipment (servers, storage, networking) inside a data center, excluding power consumed by cooling, lighting, and other mechanical and electrical infrastructure.

Critical IT load is the figure that data center leases, PUE calculations, and revenue-per-megawatt metrics are all built around, which is why it is the number quoted in colocation and wholesale contracts rather than gross facility power draw. A common misconception is treating nameplate UPS or generator capacity as the critical load figure; in practice a facility is engineered so that critical load represents only a portion of total installed capacity, with the remainder reserved for redundancy, cooling overhead, and future expansion. Owners and lenders distinguish contracted critical load (what a tenant is billed for and guaranteed) from actual utilized load (what is drawn at any given moment), and the gap between the two — unsold or underutilized power — functions as vacant space in a data center's economics even when the physical white space appears fully built out and leased.