The owners of the 110-story Sears Tower in Chicago — the tallest building in the U.S. and the Western Hemisphere — will spend $350 million to install new energy and water systems that they say will slash the tower’s electricity consumption by 80 percent and its water usage by 40 percent.

the green retrofit will replace 16,000 single-pane windows with insulated windows, install natural gas boilers with a new fuel cell technology, renovate 104 elevators and 15 escalators to cut their electricity usage by 40 percent, install new lighting that will automatically dim based on available sunlight, plant green roofs, erect wind turbines, conserve 24 million gallons of water with new plumbing fixtures and “condensation capture,” and install solar panels to heat water.