Advanced Energy Design Guide for K-12 School Buildings is the second in a series designed to provide recommendations for achieving 50% energy savings over the minimum code requirements of ANSI/ASHRAE/IESNA Standard 90.1-2004. The energy savings target of 50% is the next step toward achieving a net zero energy building, which is defined as a building that, on an annual basis, draws from outside resources equal or less energy than it provides using on-site renewable energy sources. ANSI/ASHRAE/IESNA Standard 90.1-2004 provides the fixed reference point and serves as a consistent baseline and scale for all of the 50% Advanced Energy Design Guides. This Guide focuses on K-12 school buildings and applies to all sizes and classifications (elementary, middle, high). Space types covered include administrative and office, classrooms, hallways, restrooms, gymnasiums, assembly, libraries, food preparation and dining areas. This Guide does not cover atypical spaces such as indoor swimming pools, wet labs, or dirty dry labs. The specific energy-saving recommendations are summarized in a single table for each climate zone and will allow contractors, consulting engineers, architects, and designers to easily achieve advanced levels of energy savings without detailed energy modeling or analyses. In addition, this Guide provides information on integrated design, including best practices, as a necessary component in achieving 50% energy including integrated-design best practices. A chapter on benchmarking and EUI energy targets can be used by teams who do not wish to follow the specific energy-saving recommendations. Those looking for help in implementing the climate-specific recommendations of this guide will find an expanded section of tips and approaches in the How to Implement Recommendations chapter. These tips are cross-referenced with the recommendation tables. This chapter also includes additional recommendations that identify opportunities to incorporate greater energy savings into the design of the building. Case studies and technical examples throughout the guide illustrate the recommendations and demonstrate the technologies in real-world applications.