New York’s iconic skyline is dominated by commercial high-rise office buildings. One of the engines of its economy and the home to many of the world’s leading corporate headquarters, these buildings are a foundational part of New York City’s identity.

These same skyscrapers also have a fundamental role in achieving our City and State’s climate action goals. This survey provides a diverse set of relevant deep energy retrofit case studies, from around the globe, which demonstrate how high-rise office buildings can achieve low carbon emission targets.

With the passage of the Climate Mobilization Act’s Local Law 97 in April, 2019, the City’s groundbreaking legislation to curb carbon emissions, many questions have arisen about the ability to transform New York’s existing skyline into high performing buildings with dramatically lower carbon emissions — especially our high-rise office buildings. This research team conducted a global search for deep energy retrofits of high-rise office buildings that achieved LL97’s aggressive carbon emission limits, and asked, what can we learn from them?

Building Profiles

This survey profiles eighteen projects that undertook a deep retrofit that resulted in often dramatic energy reduction. A complete facade reclad, a Midtown tenant repositioning, a Chicago upgrade and densification, a midwestern energy model calibration, a Japanese climate policy demonstration project, the comprehensive repositioning of NYC’s most iconic tower, and many more, this diverse set of retrofit projects was able to achieve an average of a 36% reduction in their site energy intensity, with several projects cutting their energy use in half.

Above: an overview of project profiles. Read the full report here.

This study’s benchmark was to find deep retrofit projects of existing high-rise office buildings that resulted in annual operational carbon emissions at or below the LL97’s 2030 carbon caps. To provide the most relevant examples, the authors chose to limit the examples to projects in a climate zone similar to New York, and, most importantly, only to include projects that had measured and verifiable pre- and post-retrofit energy data. This last requirement often proved the most challenging.

Above: profiles expand on retrofit strategies pursued, economic considerations, key findings, and reported savings- as they relate to LL97 thresholds. Read the full report here.

This survey provides several glimmers, clues, and concrete models as to how New York’s commercial high-rise office buildings can appreciably contribute to achieving these essential climate goals.

Technical Solutions

As detailed in the report’s Technical Solutions Matrix, almost all of the projects included energy efficiency upgrades to their lighting systems and controls, favored for their cost effectiveness; and most found significant carbon reductions from recommissioning, upgrading, or completely replacing their cooling systems.

Above: excerpt from the technical solutions matrix. Read the full report here.

Key Findings

Major building-wide renovation projects provide an effective vehicle for deep energy savings
Energy efficiency can be a strategic addition to major renovation projects, providing some of the deepest savings while also significantly contributing to the overall value creation.

Tenant spaces present strategic and essential savings opportunities
Tenant vacancy, turnover, or repositioning tends to be a time of reinvestment, and substantial energy savings can be found in addressing tenant spaces — a key component of a carbon mitigation plan. Tenant in place energy efficiency retrofits can be challenging, but highly effective.

Planning and analysis are foundational to a cost- effective deep retrofit
A comprehensive design and planning process is a necessary component of creating an effective deep retrofit that achieves predicted results at effective costs.

Only measured performance confers successful retrofit savings
Measured performance is hard to find, but vitally important to verify results: ‘If you don’t measure it,
you can’t manage it and you can’t fix it.

Changing context: The look forward may be different than the look back
Carbon will become a new performance metric, influencing ROI economics, technology choices, and retrofit project motivations, costs and benefits. 

Project Team

This report made possible with the generous support of New York State Energy Research and Development Authority.

Project Team
Byron Stigge, Level Infrastructure
Ryan Laber, Level Infrastructure
Richard Yancey, Building Energy Exchange
Yetsuh Frank, Building Energy Exchange
Adam Hinge, Sustainable Energy Partnerships

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