Retrofit is a process that involves updating or improving existing systems, structures, or products to enhance their performance or efficiency. This can include adding new technology, improving energy efficiency, or upgrading components to meet current standards. The goal is to extend the lifespan of the original item while making it more effective. In the context of buildings, retrofit often refers to making older structures more energy-efficient by installing better insulation, energy-efficient windows, or modern heating and cooling systems. This not only reduces energy consumption but can also lower utility costs and improve comfort for occupants.