Sears Tower – Energy Assessment of Façade Improvements

John Kooymans

The landmark Sears Tower building in Chicago, Illinois was constructed in the 1970’s with a non-thermally broken façade system and with single lite glazing panels. As a result, the structural resistance of the glass and the building envelope performance needed to be improved upon if the commercial tower were to survive as a viable property. This façade improvement study is part of an overall “greening” project which is contemplated for the tower, an action that the building owners commissioned in an effort to become more sustainable. This paper will look at the activities that Halcrow Yolles performed in an effort to assist the owners to decide what improvements to the façade could be made with minimum disruption to the existing tenants. Energy models were created for the building with data on energy costs used to establish a bench mark performance for the existing façade. Various improvements were then modeled and detailed. These ranged from glazing units (double and triple glazed), thermal performance of the existing mullion/transom system, and thermal performance of the spandrel panels. Combinations and permutations of the improvement options were then summarized and analysed with the energy costs to establish the overall energy savings and estimated pay back periods for each system improvement.

Read the full article [207 KB]

The Authors