Energy efficiency Energy efficiency indices for commercial buildings are generated without context. For instance at a quick glance it might appear that a big-box retail unit with its higher energy index is more inefficient; however, the denominator is missing. That company may generate more sales per square foot than a smaller retail outlet. In such a case energy-reduction efforts may be better focused on those institutions for whom the energy portion of expenditures represents a higher fraction of overall.
Avoiding comparing "apples with oranges", useful to find buildings of similar type of functionality across different industrial usages, for instance hospitals versus hotels. Hotels are more efficient. Why? These indices help may help provide answers across industrial usage based on overall market efficiency for the category of business detailed.