Large commercial buildings generally do not operate at economically achievable levels of energy efficiency. Performance monitoring projects have shown whole-building energy savings of 20% or more through improved operation and maintenance practices. The opportunity for O&M savings is related to systemic problems associated with the lack of feedback available from current Energy Management and Control Systems (EMCS). Today’s EMCS are designed for control, with limited capabilities in sensing, archiving, data analysis, diagnostics, and data visualization. This paper discusses a multi-year, multi-institutional project to develop and demonstrate an Information Monitoring and Diagnostics System (IMDS). The system is designed to address common O&M problems and the needs of office building owners and property managers to address these problems. The IMDS includes about 50 points of whole-building and cooling plant data, plus a set of standard diagnostics plots to evaluate key performance metrics and curves. Five unique features of the project are (1) sophisticated building operators and engineers as users, (2) permanent installation, (3) high-quality sensing, (4) high-frequency data archives, and (5) top-down design (i.e., whole building, system, and component data). The system does not provide control functions. We review the installation and early results from the use of the IMDS. An office building demonstration site was selected because of the technical reputation and interest of the chief engineer and on-site operator. We also discuss the technology adoption process and decisions involved in such innovations.