This guide was prepared under ASHRAE Special Project 140.Advanced Energy Design Guide for Small to Medium Office Buildings—Achieving Zero Energy provides strategies on achieving energy targets, setting measurable goals, hiring design teams, using simulation throughout the design and construction processes, and being aware of how process decisions affect energy usage.As in previous AEDGs, the how-to tips in this Guide address specific project aspects—building and site planning, envelope, daylighting, lighting controls, electric lighting, plug loads and power distribution systems, service water heating, HVAC systems and equipment, and renewable energy. Each section contains multiple tips that move the design incrementally toward the zero energy goal.Case studies and sidebars show how the energy goals are achievable within typical construction budgets as well as at demonstrating the technologies in real-world applications.This Guide is the second in a series of guides for achieving zero energy and is tailored to the design and creation of zero energy office buildings. It builds on the popular 50% AEDG series with new and updated recommendations on energy efficiency along with guidance about on-site renewable energy sources. The Guide establishes a set of energy performance goals for achieving zero energy. The goals are provided for all ASHRAE climate zones, in both site and source energy.Find us on Twitter #ZeroAEDG