Sears Tower Reaches for Heights of Efficiency With $350 Million Retrofit

sears towerThe Sears Tower loomed large during my childhood in the Chicago suburbs. I remember when it opened in 1973. We took a special trip downtown to see it. According to my aesthetics as a seven year old, it wasn’t very elegant and I preferred the John Hancock Tower with its swanky restaurant on the 95th floor and proximity to Marshall Fields. Then the company my dad worked for was bought by Coldwell Banker, a subsidiary of Sears at the time, and his office was moved to the Tower. I spent some quality daddy-daughter time there, and one memorable summer got paid the incredibly generous sum of $8 an hour to take the train to the city every day, do some filing and hang out downtown.

But the Tower, in my mind, never had much to distinguish it other than a great view from the 103rd floor, its height of 110 stories and the convenience of the train station. But now everything is changing.

By the end of the summer, it will no longer be the Sears Tower. It will be called the Willis Tower, named for the global insurance broker. But more importantly, the building will undergo a $350 million efficiency and renewable energy retrofit that will reduce the base building electricity use by up to 80 percent – 68 million kilowatt hours annually or 150,000 barrels of oil every year. The retrofit will also create more than 3,600 jobs in the Chicago area.


Chicago-based Adrian Smith + Gordon Gill Architecture (AS+GG) designed the retrofit strategy for the LEED certified building. Components will include:

  • Efficiency improvements to the building’s exterior envelope and windows. The tower has 16,000 single-pane windows. Sustainability plans for the building call for a window replacement and glazing program. Strategies to achieve a thermal break of the curtain wall are also being investigated. These upgrades would achieve savings of up to 50 percent of heating energy.
  • Mechanical systems upgrades in the form of new gas boilers that utilize fuel cell technologies, which generate electricity, heating and cooling at as much as 90 percent efficiency. Mechanical upgrades also will include new high-efficiency chillers and upgrades to the distribution system.
  • The tower’s 104 high speed elevators and 15 escalators that will be modernized with the latest technology to achieve 40 percent reduction in their energy consumption.
  • Water savings that will be realized with conservation initiatives through upgrades to restroom fixtures, condensation recovery systems and water efficient landscaping, which will reduce water usage by 40 percent and save 24 million gallons of water each year.
  • Lighting that will be upgraded through advanced lighting control systems and daylight harvesting, an advanced lighting control system that automatically dims lights in tenant spaces based on the amount of sunlight entering through the windows. Combined, these upgrades will save up to 40 percent of lighting energy consumption.
  • Renewable energy like wind and solar, and technologies like green roofs that will be tested. Wind turbines will be tested to take advantage of the tower’s height and unique set-back roof areas. Solar hot-water panels will help heat water for the building. Green roofs that can sustain high- altitude conditions, and that will be among the tallest in the world, will be tested to reduce storm water runoff, improve insulation, help mitigate the urban heat island effect, and provide pleasant vistas for tenants overlooking the areas.

In addition, they will add a new park at Wacker Drive and Adams Street and the Adams Street granite wall will be replaced with an interactive digital display (sounds like they’re having a bit of Millennium Park envy!), glass storefronts, and trees, which will be planted to form a landscaped terrace that will add a natural filter for carbon dioxide. A Sustainable Technology Learning Center at the building will teach visitors about ways to save energy and money. And there is also discussion of building an adjacent LEED Gold certified hotel.

Energy efficiency is nothing new for the building; since 1989, the building has reduced its annual electricity consumption by 34 percent its energy efficiency improvements since 1984 have resulted in a reduction of 51 million pounds of carbon emissions annually.

Having this as a demonstration project is critical. Buildings are the world’s largest contributors to carbon emissions. And let’s see how the financials work out. Average electricity costs in the Chicago area are 14.5 cents per kilowatt hour. The planned efficiency and renewable energy measures will save 68,000,000 kilowatt hours per year. That’s a $9,860,000 savings per year. The water conservation measures will save 24 million gallons of water. The average per gallon cost is $.0015, so that’s another $36,000 a year in savings. So the building will see immediate savings of almost $10,000,000 a year, plus some much needed modernization.

Wind turbines, solar panels, efficient windows and roof top gardens? It has taken some time, but I think the Tower has finally won me over as my favorite building in Chicago!

Image credit: cikaga jamie at Flickr under a Creative Commons license

  1. Arron

    That’s cool. I actually had no clue they did energy efficiency retrofits on skyscrapers. I read about home energy efficiency and retrofits and such regarding window replacement here.

    Anyhow I think the world’s leading cities should also adopt retrofits like this.

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