Willis Tower: Chicago, IL
Designed just prior to the energy crisis in the 1970s, the tallest building in the western hemisphere still uses many of its original major building systems. Improvements over the years have reduced overall energy use by 35%. Now, a $350 million modernization and greening project aims to save 68 million kWh per year and demonstrate how super tall buildings can improve energy performance. Upgrades are planned for the façade, mechanical systems, lighting and elevators.