Today’s climate crisis requires us to bring innovation to every part of the construction process, including our use of existing building stock. Where older buildings can be retrofitted rather than replaced, we can reinvest embodied energy and drastically reduce first costs in building energy and carbon. Drawing on Kintsukuroi, a traditional Japanese practice of repairing broken pottery with precious metals, encourages us to approach retrofit as a transformational process that brings enhanced value and new identity along with performance improvements. This session will propose Boston’s One Post Office Square, currently under construction, as a case study in this kind of transformation. We will discuss the design process and impacts on energy performance of the building’s complete envelope replacement and multiple systems upgrade.