Energy Information Systems (EIS), which can monitor and analyze building energy consumption and related data throughout the Internet, have been increasing in use over the last decade. LBNL has conducted a series of case studies of existing EIS, exploring How is the EIS used in day-to-day operation? What are the costs and benefits of an EIS? Where do the energy savings come from?This study reviews the process of these technologies from installation through energy management practice. The study is based on interviews with operators and energy managers who use EIS. Analysis of energy data trended by EIS and utility bills was also conducted to measure the benefit. This study explores common uses and findings to identify energy savings attributable to EIS, and discusses non-energy benefits as well.