Project Case Study: Empire State Building

The Empire State Building underwent a deep energy retrofit involving the remanufacturing of 6,514 windows into 'superwindows', chiller plant upgrades, and the implementation of direct digital controls. By coordinating energy upgrades with a larger $550 million remodel, the project achieved a projected 38 percent energy use reduction and annual cost savings of $4.4 million, with an incremental simple payback period of three years.

• The retrofit is projected to reduce the building's annual energy use from 88 kBtu/sf to 60 kBtu/sf, representing an expected 38 percent energy savings.
• The project achieved annual energy cost savings of $4.4 million, reducing annual utility costs from $11 million to approximately $6.6 million.
• The most innovative technical measure was the onsite remanufacturing of 6,514 windows into 'superwindows', which tripled the insulating value of each unit and reduced winter heat loss by at least two-thirds.
• The project utilized a 'right steps in the right order' approach, prioritizing the reduction of thermal loads (via windows and radiant barriers) before upgrading to more efficient systems like VAV air handling units and chiller retrofits.
• Financial viability was ensured by 'piggybacking' energy upgrades onto a larger $550 million planned remodel, resulting in an incremental simple payback for the energy retrofit of three years.
• The design team used energy modeling (DOE-2.2/eQUEST) and Life Cycle Cost Analysis (LCCA) to evaluate over 70 potential efficiency measures, eventually selecting a 'NPV Mid' package that balanced CO2 reductions with financial constraints.

APA

Harrington, E., & Carmichael, C. (2009). Project Case Study: Empire State Building. RMI. https://rmi.org/app/uploads/2017/04/Buildings_Retrofit_EmpireStateBuilding_CaseStudy_2009.pdf

Chicago

Harrington, Eric, and Cara Carmichael. Project Case Study: Empire State Building. RMI, 2009. https://rmi.org/app/uploads/2017/04/Buildings_Retrofit_EmpireStateBuilding_CaseStudy_2009.pdf.

Wikipedia

{{cite report |last1=Harrington |first1=Eric |last2=Carmichael |first2=Cara |title=Project Case Study: Empire State Building |publisher=RMI |date=2009 |url=https://rmi.org/app/uploads/2017/04/Buildings_Retrofit_EmpireStateBuilding_CaseStudy_2009.pdf |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{harrington2009project, author = {Harrington, Eric and Carmichael, Cara}, title = {{Project Case Study: Empire State Building}}, institution = {RMI}, year = {2009}, url = {https://rmi.org/app/uploads/2017/04/Buildings_Retrofit_EmpireStateBuilding_CaseStudy_2009.pdf}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }