\The energy utilization index (EUI) is commonly used to describe a building's energy performance. This index is not without shortcomings, as it does not adequately address issues such as space utilization, occupant density, or irreducible process loads. This paper explores the use of a bottom-up approach for energy benchmarking, both for design optimization and portfolio analysis, utilizing a concept known as energy usage effectiveness (EUE). The EUE metric is based on the ratio of a building's total energy use divded by an adapted calculation of process energy use. Benchmark EUE values will be calculated based on the Department of Energy's Commercial Reference Building's for new construction, existing buildings "post-1980" and existing buildings "pre-1980s." The full range of ASHRAE climate ones will be represented for all of the major building types available. EUE will be compared to calculated EUI, to highlight correlations and divergences in the outcome data. The EUE concept will also be applied to data from a heavily sub-metered high-performance building, as well as public data published in ASHRAE high-performance building case studies.