This project addresses the development of advanced fabrication capabilities for energy saving electrochromic (EC) windows. SAGE EC windows consist of an inorganic stack of thin films deposited onto a glass substrate. The window tint can be reversibly changed by the application of a low power dc voltage. This property can be used to modulate the amount of light and heat entering buildings (or vehicles) through the glazings. By judicious management of this so-called solar heat gain, it is possible to derive significant energy savings due to reductions in heating lighting, and air conditioning (HVAC). Several areas of SAGE’s production were targeted during this project to allow significant improvements to processing throughput, yield and overall quality of the processing, in an effort to reduce the cost and thereby improve the market penetration. First, the overall thin film process was optimized to allow a more robust set of operating points to be used, thereby maximizing the yield due to the thin film deposition themselves. Other significant efforts aimed at improving yield were relating to implementing new procedures and processes for the manufacturing process, to improve the quality of the substrate preparation, and the quality of the IGU fabrication. Furthermore, methods for reworking defective devices were developed, to enable devices which would otherwise be scrapped to be made into useful product. This involved the in-house development of some customized equipment. Finally, the improvements made during this project were validated to ensure that they did not impact the exceptional durability of the SageGlass® products. Given conservative estimates for cost and market penetration, energy savings due to EC windows in residences in the US are calculated to be of the order 0.026 quad (0.026×1015BTU/yr) by the year 2017.