Chicago’s Studio Gang decided to follow the sun when planning a 26-story apartment building, and determining how to cut back on its energy usage in a city challenged by big seasonal shifts in temperature. Taking into account the changing angles of the rays as the sun increasingly drops and lifts the apex of its path according to the season, they created a facade to maximize or minimize the 250 apartments’ exposure to the sun’s heat in line with seasonal temperatures ranging from an all-time low of -27 °F to a high of 105 °F, in order to reduce dependence on energy-consuming heating and cooling systems, and artificial lighting.

Facade Windows Angled to Match Sun’s Path
To accomplish this, the facade of the aptly named Solstice Tower in Hyde Park is made up of floor-to-ceiling glass windows angled to match the rays’ 72 degree angle (determined by Chicago’s latitude) on the summer solstice or longest day of the year, and at the same time accommodate the 42 degree sun’s angle when the sun follows its lowest path across the sky and sunrise and sunset are separated by the year’s shortest day, during the winter solstice.

