PURPOSE AND SCOPE In 2010@ ASHRAE published Performance Measurement Protocols for Commercial Buildings (2010a)@ which describes what to measure@ how it is to be measured@ and how often it is to be measured to quantitatively assess the performance of commercial buildings. This follow-on book is a working guide to help users implement the protocols outlined in Performance Measurement Protocols for Commercial Buildings by providing tools and techniques for measuring@ managing@ and improving the performance of a facility@ as demonstrated by its energy and water use and indoor environmental quality (IEQ). Thus@ it provides best practices for facility managers and operators to evaluate and improve the performance of commercial buildings throughout their service life. It is also intended to support integrated commissioning (Cx)@ as implemented in the existing building commissioning (EBCx) process@ and all activities of the building's operation and maintenance team. This Guide presents step-by-step procedures at three process levels of performance@ which are intended to match the level of cost and intensity of effort for a range of types and sizes of facilities: Basic Evaluation is the basic@ indicative level that uses observations of building characteristics@ perceptions of occupants@ and data from utility bills to characterize performance. Diagnostic Measurement is the intermediate@ diagnostic level that uses physical measurements to diagnose problems indicated at the Basic Evaluation level and to characterize performance relative to physical standards so as to identify how performance can be improved. Advanced Analysis is the advanced@ investigative level using the results of the first two levels plus the results of professional investigative processes to characterize performance and identify specific actions for performance improvement. This Guide covers all facility energy-using systems@ water-using systems@ and systems that affect IEQ@ as well as the measurement and operating techniques for energy and water conservation and IEQ improvement. It provides guidance@ tools@ and aids for building facility mangers@ operators@ technicians and consultants to continuously monitor and improve facility performance. The appendices include measurement and instrumentation specifics@ detailed procedures@ and examples of forms@ worksheets@ and checklists. The standardized forms@ worksheets@ and checklists are also available in Microsoft? Excel? format on the Workbooks and Resources CD that accompanies this Guide to simplify@ facilitate@ and expedite the evaluation@ measurement@ and improvement procedures.