Energy Reuse Effectiveness (ERE) is a measure of the energy reused in data centers
. There are various approaches to reuse the energy consumed in data centers for other measures. For example, waste heat from cooling is often used to heat office buildings. The reused energy does not flow into the energy balances of the Power Usage Effectiveness (PUE) or the Energy Usage Effectiveness
(EUE) and thus distorts the key figures. In the calculation of the Energy Reuse Effectiveness (ERE), the entire energy consumption of the data center is broken down individually. This includes the energy consumption of the cooling systems, the general power supply and lighting, and the computer systems. The ERE value is calculated from the total energy minus the reused energy to the energy demand of the computer systems and IT equipment.