Still, data centers will have the option to provide information about their level of redundancy -- or tier level -- "so we can analyze that data further if we feel we need to account for it in future models," Sullivan said.
In other words, the EPA will tweak its methods over time if it needs to.
Gary Murphy, principal with idGroup, a firm that designs data centers, called the program "very useful." It will give data center managers a way to show C-level executives -- who are paying more attention to data-center energy bills -- that they are running an efficient facility, he said.
But he also wondered if the EPA collected enough data for its analysis. "A hundred and eight data centers isn't a lot," he said.
The EPA will add the data center criteria to its Portfolio Manager tool in June, and organizations that want to take part can enter their data to find their score.
The Energy Star program is also recognized in Europe. Andrew Fanara, who leads the program at the EPA, said China and India have also agreed "in principle" to use the EPA's system to rank products. Avoiding a patchwork of regional programs is important, he said, especially for multinational companies.