critical metric for data center ◦ Facility’s total power delivered divided by its IT equipment power usage, and the lower this figure is, the better. ◦ A PUE rating of 1.0 would be equivalent to a 100 percent efficient facility. ◦ Data centers average about 1.67, which means that for every 1.67 watts of electricity drawn by the facility, only 1 watt is being delivered to IT equipment.