Winthrop Center
Boston
Merit Award
Sent by: DeSimone Consulting Engineering
Owner: Millennium partners
Main design: Handel Architects
General contractor: Suffolk
Civil Engineer: Nitsch Engineering
Structural Engineer: DeSimone Consulting Engineering
MEP Engineer: WSP
Associate Architect: DREAM Collaborative
Underground engineering: Haley and Aldrich
passive house: Steven Winter Associates
The 53-story, 1.8 million-square-foot tower is the world’s largest Passive House office building that also meets WELL Gold and LEED Platinum standards, the filing says. It includes custom energy recovery ventilation, “high performance” doors and windows, and “continuous” insulation. Conservation features cut water consumption in half. A typical Class A building in Boston uses 164 percent more energy, the team says.
The city’s fourth-tallest building at 691 feet meets federal height limits with maximized rentable space. Cast-in-place concrete for the primary structure helped increase floor-to-floor heights, adding five more stories than would have been possible with steel.

Photo courtesy of Desimone Consulting Engineering
The building program provided for office and residential floors. To unify the incongruous column grids required by this combination, the team designed a 10,000-ton dual-purpose “sky mat” system, a first in Boston. A steel-frame roof directly above a three-story block entrance at street level is supported by mega-columns and creates a platform that supports the concrete tower above.
The $1.3 billion project was completed on budget and on schedule in more than four years, despite a pause during the COVID-19 pandemic.
