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A report by The Climate Group on behalf of the Global e-Sustainability Initiative (GeSI), with independent analysis by McKinsey & Company

The Climate Group

Empire State Building Retrofit

Key Facts

  • Built during the Great Depression, the Empire State Building symbolizes America's limitless potential. Today the building is undergoing a major sustainability retrofit to become a leading example of economic and environmental revitalization. Consulting, design, and construction partners Clinton Climate Initiative (CCI), Johnson Controls Inc. (JCI), Jones Lang LaSalle (JLL), and Rocky Mountain Institute (RMI), recently completed an 8 month modeling and analysis project which will save up to 38 percent of the building's energy and $4.4 million annually. See for more info
  • A total of 8 projects were implemented:

    1. Daylighting, lighting & plugs: 2060 tCO2/yr, $941k/yr savings
    2. Building windows (insertion of thin film & gas between existing panes for each window): 1150 tCO2/yr, $410k/yr savings
    3. Radiative barriers (redirect heat away from walls): 480 tCO2/yr, $190k/yr savings
    4. Chiller plant retrofit (smaller load needed): 1430 tCO2/yr, $676k/yr savings
    5. Air handling units (newer, fewer units): 1520 tCO2/yr, $703k/yr
    6. Tenant energy management (submetering to provide online info): 743 tCO2/yr, $387k/yr
    7. Demand control ventilation (using CO2 sensors to determine occupancy): 300 tCo2, $117k/yr
    8. Other digital controls save an additional 1900 tCO2 and $741k/yr The listed components were identified after an 8 month modeling study, and completion of energy-efficiency retrofit (begun in Autumn, 2009) will take less than 24 months
  • The project took 24 months to implement
  • For the overall solution, the likely ROI is 3 year payback (based on incremental cost of $13.2M / annual savings of $4.4M)
  •  A number of additional benefits were noted:

    • Enhanced thermal comfort to occupants
    • Demand control ventilation will improve indoor air quality by ensuring adequate, though not excessive, ventilation
    • A high-quality visual environment will be provided through tenant lighting and daylighting efforts that layer ambient, direct/indirect, and task lighting to maximize comfort
    • The recommended package of measures also reduces the building’s peak electric demand by approximately a third, freeing up currently constrained electrical capacity.
  • The actual (or likely) cost of the project is $20M performance contract with Johnson Controls, but incremental cost to Empire State Building is $13.2M (some funds made available from existing capital investment plan)
  • The actual (or projected) savings from the project are $4.4M annually
  • The primary sponsor for the project was Stephen A. Roell, President and CEO of Johnson Controls, made a personal commitment to the project. - Anthony Malkin, ESB owner, was an active, enthusiastic and committed champion for the project.

What was the impact?

  • Did you use a specific methodology or third party to calculate CO2e or KWh savings?

    We will be measuring and verifying energy savings over a fifteen year period using the international performance measurement and verification protocol (IPMVP). If there is an energy savings short-fall, Johnson Controls will be responsible for making up for the difference. We are using option D, calibrated simulation and other options based on the specific improvement measure. We used a calibrated energy simulation model (DOE-2) to estimate energy usage and then e-grid emission factors to estimate scope 1 and 2 GHG reductions.
  • Comments on energy savings

    19 percent savings in KWh in the initial phase, and gradually increase the savings to 38 percent once the longer-term projects are completed. The improvements will place the Empire State Building in the top 10 percent of U.S. commercial office buildings in terms of energy efficiency.
  • 105,000 t CO2e has been saved on this project
  • Notes about Carbon savings/calculations

    Savings will accrue over a 15 year period
  • The project has internal verification for results

Making it Happen

  • The following regulations or incentives allowed the business case to be more attractive

    Johnson Controls received rebates from NYSERDA
  • Barriers experienced during the initiation of the project

  • Comments regarding barriers

    Additional barriers include:

    • lack of as-built building information
    • time commitment - 60+ improvement measures were rigorously evaluated through calibrated simulation
    • familiarity with performance contracting methods and a bundled project approach
    • coordination of the multi-organization, integrated design team (highly valuable in the end)
    • cost-effectiveness of renewable energy and other advanced technology solutions (would have liked to apply them but couldn't justify)
  • How were they overcome?

    ESB (Empire State Building) models were created to simulate the building’s energy, compute greenhouse gas reductions, and determine capital and operations cost implications. Public Domain Simulation Tools are available at
  • What were the key lessons learnt?

    Developing robust solutions requires the coordination of several key stakeholders. In the Empire State Building, the project team included engineers, property managers, energy modelers, energy efficiency experts, architects, and building management. Each of these stakeholders was needed to help build a robust energy model that addressed the building’s changing tenant profile and helped the team model the impacts of its energy efficiency strategies. Coordination also included the tenants. Involving tenants and considering their perspective early on is critical because more than half of the energy efficiency measures that will be implemented at the Empire State Building involve working both with tenants and within their spaces.

    For an energy efficiency retrofit to be cost effective, the retrofit needs to align with the planned replacement or upgrades of multiple building systems and components. Since these upgrades were already going to be carried out, the team redesigned, eliminated and created projects that cost more than the initial budget but had significantly higher energy savings over a 15-year period. However, the energy savings are not substantial enough to offset the full capital cost, because doing energy efficiency projects well before major systems and components are ready for replacement will likely be cost prohibitive. Capturing these reductions in a profitable manner demands careful planning and coordination to ensure that energy efficiency retrofits align with building replacement cycles.

    In the Empire State Building, maximizing profitability from the energy efficiency retrofit leaves almost 50 percent of the CO2 reduction opportunity on the table. The building owner, while still selecting an optimal package of measures with a high net present value, sacrificed 30 percent of profit to deliver more CO2 reductions and improve the lighting and tenant comfort within the building. Changes in energy prices and/or the cost of energy efficiency technologies may help to better align profit maximization and CO2 reduction. However, as things stand currently, there is a gap between the socially desirable amount of CO2 reduction and the financially beneficial amount of CO2 reduction from a building owner’s perspective.

    Having completed the recommendations for the Empire State Building, the project team recognizes a number of opportunities for condensing the study period, for example: developing experienced teams, creating tools for rapidly diagnosing and categorizing a building (or a portfolio of buildings), quickly developing a “first-cut answer,” and developing and using tools to quickly iterate between financial and energy modeling to arrive at the optimal package of measures.

    The financial decision-making tool helped the team to understand that the recommended package of energy efficiency measures would not significantly change even if there were carbon regulations leading to higher energy prices over time. Carbon regulation that changed energy prices by less than two percent per year had little effect on the financial performance of the modeled packages.


Project Type
Solution Type
Smart Building
Carbon Saved
105,000 t CO2e

“What makes this an innovative, replicable model for other commercial buildings is the process and complete system-wide approach to identifying optimal energy efficiency improvement measures, as compared to component by component,” stated Iain Campbell, Vice President and General Manager, Global Energy and Workplace Solutions, Johnson Controls, Inc. “Looking at the interaction of different measures allows smarter decisions regarding retrofitting buildings.”


Company Name
Johnson Controls

A provider of clean technologies or services

"Johnson Controls provides innovative automotive interiors that help make driving more comfortable, safe and enjoyable. For buildings, it offers products and services that optimize energy use and improve comfort and security. Johnson Controls also provides batteries for automobiles and hybrid electric vehicles, along with systems engineering and service expertise".

  • Empire State Building LLC

    The Empire State Building is a 102-story landmark Art Deco skyscraper in New York City at the intersection of Fifth Avenue and West 34th Street. Its name is derived from the nickname for the state of New York. It stood as the world's tallest building for more than forty years. The Empire State Building has been named by the American Society of Civil Engineers as one of the Seven Wonders of the Modern World. The building and its street floor interior are designated landmarks of the New York City Landmarks Preservation Commission. It was designated as a National Historic Landmark in 1986.
  • Clinton Global Initiative

    Building on President Clinton’s lifetime in public service, the Clinton Global Initiative (CGI) reflects his belief that governments need collaboration from the private sector, non-governmental organizations, and other global leaders to effectively confront the world’s most pressing problems. After attending thousands of meetings during his career in which urgent needs were discussed but no action was taken to solve them, President Clinton saw a need to establish a new kind of meeting with an emphasis on results.
  • Rocky Mountain Institute

    Rocky Mountain Institute ® (RMI), a 501(c)(3) nonprofit organization, was established in 1982 by resource analysts L. Hunter Lovins and Amory B. Lovins. What began as a small group of colleagues focusing on energy policy has since grown into a broad-based institution with approximately eighty full-time staff, an annual budget of nearly $12 million (over half of it earned through programmatic enterprise), and a global reach.
  • Jones Lang LaSalle

    Jones Lang LaSalle is a financial and professional services firm specializing in real estate services and investment management. Our more than 30,000 people in 750 locations in 60 countries serve the local, regional and global real estate needs of those clients, growing our company in the process. In response to changing client expectations and market conditions, we assemble teams of experts who deliver integrated services built on market insight and foresight, sound research and relevant market knowledge. We attract, develop and reward the best, and most diverse, people in our industry, challenging them to develop enduring client relationships built on quality service, collaboration and trust.