“The 9-inch-thick balcony slabs thin out as they extend from the cladding line to the edge of the cantilever. This profile helps in drainage, notes structural engineer, David Eckmann of Magnusson Klemencic in Chicago, and keeps rainwater off the face of the building. The thin concrete slabs do tend to lose heat in the winter, Gang acknowledges. The architects and their consultants investigated adding thermal breaks between the indoor and outdoor concrete slabs, but this strategy proved too difficult to achieve for this project. Gang maintains, however, that in terms of overall energy use, the heat loss in the winter is offset by savings in air-cooling in the summer owing to the concrete canopies, the glazing, and the natural ventilation.”

I believe that is fair to give the benefit of the doubt to a certified LEED Acredited profesional as is Jeanne Gang, that the issue was properly addressed.

http://greensource.construction.com/green_building_projects/2010/1001_Aqua-Tower.asp