According to the U.S Department of State, buildings account for an estimated 36 percent of overall energy use, 65 percent of electricity consumption, 30 percent of all greenhouse gas emissions and 12 percent of water use in America. Green improvements to Sears Tower are aimed at reducing electricity use by 80% in just four years, equating to 68 million kilowatt hours or 150,000 barrels of oil per year. The architects firm responsible for the retro-design, Adrian Smith + Gordon Gill Architecture, has also designed a 50 storey highly sustainable tower to accompany Sears Tower on its south side which will draw power from the improved efficiency measures and work as a net-zero energy development.

Sears Tower's Chicagoan neighbour, Merchandise Mart, was an earlier example of monumental eco retrofitting in America gaining LEED Silver and becoming the world’s greenest certified commercial building. As the world's tallest tower for 24 years, the retrofitting of Sears Tower will be a significantly larger undertaking, with all 110 stories incorporated in the changes.

Improvements include removing all 16,000 single-pane windows and swapping with modern replacements, modernizing the tower's 104 high speed elevators, harnessing renewable energy through turbine and solar technology, introducing green roofs to reduce storm water run-off and improve insulation as well as creating the world's tallest vistas for tenants and upgrading facilities throughout to use more efficient technology.