This document discusses various energy efficient techniques that can be implemented when retrofitting existing academic buildings, including passive solar techniques like building orientation, trombe wall construction, solar chimneys, and earth air cooling tubes. It also discusses active systems like photovoltaic cells, as well as improvements to the building envelope like double glazed windows, insulation, and shading. Implementing these techniques could potentially save 40-50% of a building's energy usage and reduce costs through lower energy bills and shorter payback periods of 5-8 years for the upgrades. The document provides details on several techniques and cites other literature reviewing green building examples in India incorporating these strategies.