The modernization of a mid-century Midtown Manhattan office tower features a new façade intended to improve occupant comfort and reduce energy consumption. The building, at 666 Fifth Avenue, was originally designed by Carson & Lundin.
First opened in November 1957 when it was considered cutting-edge, the original façade of the 500-foot-tall modernist skyscraper was highly inefficient by today’s energy efficiency standards. Using an early version of a semi-unitized curtain wall, the old façade featured units with punched aluminum panels on the bottom and a single glass pane on top. This was advantageous in its light weight, but yielded poor energy efficiency. The project team chose a full reskinning as the best option to upgrade the aging building.
The new façade features the largest single-pane units ever used on an office development in New York City, according to a blog post at KPF.com. These large panes created efficiencies in construction, logistics, and structural detailing. Panel fabricators used a single cut, yielding only minimal waste when producing each unit. Situated inside a four-sided shadowbox, the panels span the full width between columns and the full height between floors. This approach tripled the window area, bringing in plentiful daylight for tenants.
Other improvements on the 1.2 million-sf office tower include:
- Mechanical upgrades for high-efficiency heating and air systems that draw in greater quantities of fresh air.
- A reconstructed lobby with modernized elevators that will support a retail space.
- Numerous columns and low ceilings were eliminated from office floors to maximize interior space.
- Some units offer double-height spaces and interconnected floors, taking advantage of the building’s wide range of floor plate sizes.
- Designers used existing massing—a podium and tower interspersed with multiple setbacks—to create exterior terraces at multiple levels on three sides.
“One of the important aspects of an adaptive reuse project is finding the existing value in a building, and identifying areas that can create more desirable space for users," said KPF Principal Lauren Schmidt, AIA, LEED AP BD+C. "The existing façade at 660 Fifth Avenue was one of the first curtain wall systems when it was built in the 1950s and very modern at the time, but it had limitations in terms of thermal and acoustical insulation, as well as small windows. We approached the façade as a clean slate and proposed opening it up completely with units that would span column to column. This, in a sense, allowed the columns to disappear and create open views. It was a great opportunity to propose something that was perhaps considered atypical, but actually, as we worked through the logistics of it, made sense for a number of reasons and was highly efficient.”
On the team:
Client: Brookfield Properties
Design Architect (full services): Kohn Pedersen Fox (KPF)
MEP Engineer: Cosentini Associates
Structural Engineer: Gilsanz Murray Steficek (GMS)
General contractor: Turner Construction

















Related Stories
Giants 400 | Jan 23, 2024
Top 110 Medical Office Building Architecture Firms for 2023
SmithGroup, CannonDesign, E4H Environments for Health Architecture, and Perkins Eastman top BD+C's ranking of the nation's largest medical office building architecture and architecture engineering (AE) firms for 2023, as reported in the 2023 Giants 400 Report.
Office Buildings | Jan 19, 2024
How to strengthen office design as employees return to work
Adam James, AIA, Senior Architect, Design Collaborative, shares office design tips for the increasingly dynamic workplace.
Adaptive Reuse | Jan 18, 2024
Coca-Cola packaging warehouse transformed into mixed-use complex
The 250,000-sf structure is located along a now defunct railroad line that forms the footprint for the city’s multi-phase Beltline pedestrian/bike path that will eventually loop around the city.
Sponsored | BD+C University Course | Jan 17, 2024
Waterproofing deep foundations for new construction
This continuing education course, by Walter P Moore's Amos Chan, P.E., BECxP, CxA+BE, covers design considerations for below-grade waterproofing for new construction, the types of below-grade systems available, and specific concerns associated with waterproofing deep foundations.
Biophilic Design | Jan 16, 2024
New supertall Manhattan tower features wraparound green terraces
At 66 stories and 1,031.5 ft high, The Spiral is BIG’s first supertall building and first commercial high-rise in New York.
Sustainability | Jan 10, 2024
New passive house partnership allows lower cost financing for developers
The new partnership between PACE Equity and Phius allows commercial passive house projects to be automatically eligible for CIRRUS Low Carbon financing.
MFPRO+ Special Reports | Jan 4, 2024
Top 10 trends in multifamily rental housing
Demographic and economic shifts, along with work and lifestyle changes, have made apartment living preferable for a wider range of buyers and renters. These top 10 trends in multifamily housing come from BD+C's 2023 Multifamily Annual Report.
Green | Dec 18, 2023
Class B commercial properties gain more from LEED certification than Class A buildings
Class B office properties that are LEED certified command a greater relative benefit than LEED-certified Class A buildings, according to analysis from CBRE. The Class B LEED rent advantage over non-LEED is about three times larger than the premium earned by Class A LEED buildings.
Office Buildings | Dec 12, 2023
Transforming workplaces for employee mental health
Lauren Elliott, Director of Interior Design, Design Collaborative, shares practical tips and strategies for workplace renovation that prioritizes employee mental health.
Office Buildings | Dec 11, 2023
Believe it or not, there could be a shortage of office space in the years ahead
With work-from-home firmly established, many real estate analysts predict a dramatic reduction in office space leasing and plummeting property values. But the high-end of the office segment might actually be headed for a shortage, according to real estate intelligence company CoStar Group.