American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) added data centers to their building efficiency standard, ASHRAE Standard 90.1. This standard defines the energy efficiency for most types of buildings in America and is often incorporated into building codes across the country. Data centers are among the fastest-growing users of energy, according to an EPA report, and most data centers have historically been designed and operated without regard to energy efficiency (for details, see this 2009 EPA Energy Star survey). Thus, setting efficiency standards for data centers is important, and we welcome this step. “we believe that an overall data center-level cooling system efficiency standard needs to replace the proposed prescriptive approach to allow data center innovation to continue. The standard should set an aggressive target for the maximum amount of energy used by a data center for overhead functions like cooling. In fact, a similar approach is already being adopted in the industry,” notes Google.