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Empire State Realty Trust's (ESRT) goal is to achieve net-zero carbon emissions across its 10.1 million square foot portfolio by 2035 (more on ESRT's Sustainability program here).  Learn more about how ESRT evaluated the technical and economic potential to achieve carbon neutrality at five of their buildings, including the Empire State Building.

  • Central systems may present more opportunities for optimization based on automation and controls sequences.

  • High performance standards: Consistent rollout of high-performance standards is crucial:
    • Key internal and external service providers (fit out designers, controls vendors, maintenance contractors, lease negotiators) require technical oversight to ensure all their work supports energy and carbon efficiency goals.
  • Tenant designs: Small deviations of tenant designs from energy code and tenant design guidelines can build up to significant impediments to achieving carbon savings.
  • Small decisions add up to big impact: Consider long-term ROI and operational consequences of first-cost decisions on all projects.  
Contributing Organizations

Empire State Realty TrustBuro HappoldJohnson ControlsLuthin AssociatesQuest Energy Group Reos PartnersSkanska

Building the Decarbonization Roadmap for the Empire State Building

The Empire State Realty Trust and their team of consultants shown above, followed the Playbook approach to define the decarbonization roadmap for their flagship office building: the Empire State Building. The iconic landmark consists of 102 stories totaling 2.8 million gross square feet, among which 1.8 million square feet of rentable space.


Getting Started

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The ESRT management team took great care to assemble a project team with deep expertise that could handle the level of complexity, interdisciplinary thinking, and innovation needed to tackle the challenge of bringing the Empire State Building as close as possible to its carbon neutrality goal. The core project team consisted of:

  • ESRT, building owner and facilities team
  • Buro Happold Engineering, global leader in whole building systems engineering
  • Quest Energy, energy modeling consultant
  • Skanska, constructability and cost analysis consultant
  • Luthin, grid, tariff, rate, tax, and carbon emissions fine (LL97) expertise
  • Johnson Controls, BMS vendor and consultant
  • Tabla Raza, external consultant specializing in innovative solutions with technology
  • Reos Partners, facilitation and support of collaborative meetings

Additional support was provided by:

  • Trystate Mechanical, mechanical contractor assisted in pricing ECMs
  • Robert Clarke Associates, leading expert in the application of architectural glass technology to sustainable design
  • Mosto Technologies, energy consult specializing in commercial steam systems in NYC
  • Sentient Buildings, energy management consultant providing real-time building automation that enables advanced monitoring and management solutions
  • Cortex, energy management consultant providing real-time energy monitoring software and system recommendations
  • US Chillers, global chiller and energy solutions provider
  • Lutron, leading expert in lighting design
  • Sapient, external consultant specializing in plug load management
  • Wint, water management consultant

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Building Discovery

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Learn the Building

The project team assessed the existing conditions and systems of the Empire State Building. The team reviewed the following items:

  • Operating schedule
  • Building and energy management systems
  • Cooling systems
  • Heating systems
  • Ventilation systems
  • Lighting
  • Plug loads
  • Tenant IT loads
  • Domestic hot water
  • Envelop system

Here is a quick summary of the current building HVAC system:

  • Offices and base building up to floor 79:
    • Steam radiators supplied by district steam
    • VAV chilled water AHUs
    • Electric drive centrifugal chillers located in the cellar separately serving three pressure zones with a common condenser water system
    • Steam chillers as backup only
  • Retail:
    • Water-cooled DX
  • 80th floor and above:
    • Multiple air-cooled chillers serving multiple systems including observatory
    • Some self-contained air-cooled DX in some broadcast areas

Build the "Business-as-Usual" Base Case

Utility Analysis (Existing Condition) - The project team analyzed the building utility data for baseline year of 2019 to evaluate the breakdown of energy usage, utility costs and resulting carbon emissions by fuel source (i.e., gas, steam, and electricity – broadcast electricity usage was also broken out at the request of the owner). Electricity energy usage made up the majority of the energy consumption at 63.2%, while stea