This chapter provides guidelines for developing building monitoring projects that provide the necessary measured data at acceptable cost. The intended audience comprises building owners, building energy monitoring practitioners, and data end users such as energy and energy service suppliers, energy end users, building system designers, public and private research organizations, utility program managers and evaluators, equipment manufacturers, and officials who regulate residential and commercial building energy systems. A new section has been added on small projects to show how the methodology can be simplified. Reasons for Energy or Water Monitoring Small Projects Protocols for Performance Monitoring Common Monitoring Issues Steps for Project Design and Implementation