Willis Tower at Chicago, USA is the second tallest building in the West Hemisphere. Willis Tower opened the Willis Tower Greening Project to put green elements and to save energy consumption in this building. Owners of this tower selected Adrian Smith + Gordon Gill Architect for their Willis Tower greening project. The mission of Adrian Smith + Gordon Gill was updating this landmark building.
Update components were efficiency improvements of windows and envelope, mechanical systems upgrade, elevator and escalator, water savings and lighting. This update included the reducing electricity usage by 80 percent which is about 68,000,000 KW.
During the updating, they built a hotel on the south side of the tower. The interesting part about that 50-story five-star hotel is that their net energy consuming is zero. Because this building is operated by the energy savings from the project.
Also, the new hotel features include green elements such as sky gardens, solar deck, green roofs/planting terraces, and building-integrated wind turbines.