From air conditioners to electrical panels to data centers, engineers routinely specify equipment bigger than the job requires, to cover uncertainty, future growth, or plain caution. The result is wasted capital and, because most equipment spends most of its life running well below full capacity, wasted energy too. Researchers from Lawrence Berkeley National Laboratory and the U.S. Department of Energy look at why oversizing is so common and group the ways to fix part-load inefficiency into three categories. They also propose a new Part-Load Metric: a single number that shows how far a device’s real-world efficiency falls from its design efficiency, so different technologies and solutions can be compared directly.