Points out that the deregulation of the electricity industry in the U.S. is fuelling real-time pricing (RTP) pricing structures, and is prompting a need for automated control systems that respond to the diversity of loads. Describes the work of an industry/government consortium to develop and install an RTP-sensitive control system in a large New York hotel. Evaluates the results by comparing a four-year period with automated RTP control with the preceding four years. Finds significant reductions in electricity consumption and costs can be achieved even when only a portion of the building and its mechanical and lighting systems are controlled in response to RTP. Notes the need for commitment on the part of the building operating staff.