Solar energy is set to play an ever-increasing role in the appearance and construction of buildings. This guide, which focuses on architecture in the U.K., provides an overview of how photovoltaics work and how they are incorporated in the design of buildings. Intended for designers, clients, and students, it outlines the basic principles of photovoltaic design in architecture. It also discusses the potential and the challenges of using photovoltaic building design as a way to promote the use of solar energy.