As outlined in the previous section entitled The Overall Plan, Twin Embraces attempts from its most foundational planning to set forth a comprehensive organization that supports environmental sustainability.  These features range from providing equal access to natural light, to organizing functions according to solar need and orientation, to advanced district-level heating and cooling.  The Wintergarden feature is the keystone, providing thermal solar collection, as well as a heat sink and thermal buffer for the regular acceptance of large crowds.

On an architectural level, the design follows suit.  Fenestration is kept to responsible levels for Chicago’s climate zone, and is tuned in size, height, and orientation to the associated interior functionality.  Light shelves and clerestories are used throughout high-ceilinged spaces purposely limited to shallow depths, to facilitate passive daylighting.  Adverse effect from oversized glazing at ground level, so critical to creating inviting retail spaces, is offset by the bulk of these windows being oriented into the Wintergarden, where the semi-conditioned space’s moderated internal climate results in a superior temperature differential.  Parking and other exterior implements, such as stair towers, are freestanding and set beyond the thermal envelope, reducing complicated thermal bridging and its attendant energy loss.

All structures, except for the foundation and presidential offices, assembly domes, and the Beacon of Hope Tower, are comprised of heavy timber members and cross-laminated timber decks.  A unique, long-span structural system of massive arched trusses has been devised for the grandest spaces, 96 feet across, supporting active intensive green roofs in addition to interior floors below.  These systems consolidate loads and reduce the use of concrete, which in general has been kept to a minimum.

Glass used throughout is of the latest bird-friendly type; complex double curvature at the fully glazed areas helps improve avian prospects and presents an intriguing architectural outcome, where strict hexagonal forms morph into pure volumetric spheres and cylinders.  This approach helps to reduce exterior surface area and provides the greatest practical volume, following a rigorous structural logic.  It also directly integrates with the modular nature of the design, solving a common challenge associated with the awkward interface of domes and other rectilinear elements.

Onsite greywater management and treatment plants, located in the underground levels, permit elevated water management strategies to occur, exceeding almost all facilities in the State of Illinois.  Recaptured water is used for onsite irrigation, water closets, and ecological features throughout the grounds.