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Future Research

After nine months of extensively studying and evaluating the Empire State Building, the project team has discovered several research topics that could help accelerate greater carbon savings across the U.S. and global existing commercial building stock.

The project team realizes many other groups and projects are attempting to address similar issues. To comment on your work in these areas, please email, and we will update the research site accordingly.

Capturing Tenant Energy Savings

In existing commercial buildings, capturing many profitable energy efficiency opportunities requires engaging with tenants. In the Empire State Building retrofit, over 50 percent of the opportunities required some level of tenant engagement. Often energy efficiency opportunities that require tenant engagement are not implemented because of numerous real or perceived barriers including split incentives, business interruption, etc.

Research is needed to collect case studies demonstrating the business case for engaging tenants in building retrofits. In addition, best practices and recommendations for engaging tenants could help spur building owners to pursue tenant energy savings potential. In the team's experience, recommendations could include a set of actionable items such as sub-metering, creating green lease rider templates, creating programs to incentivize and engage tenants, etc. that will help owners and operators overcome real and perceived barriers to engaging tenants in energy efficiency projects.

Energy Efficiency Retrofit Measures: Why do some typically make the cut and others don't and what can be done to increase the pool of opportunities?

In a typical energy efficiency retrofit project led by an ESCO, the ESCO focuses on upgrading lighting systems and HVAC controls1,2.

This focus can usually generates 15-20 percent reduction in a building's utility bills. In the Empire State Building retrofit, the team initially conjured up more than 50 potential energy efficiency retrofit measures. Rigorous energy and financial analyses whittled the list down to only eight measures that will generate approximately 38 percent reduction in the Empire State Building's utility bills. Why did the other 42 not make the cut? Why do most retrofit projects fail to incorporate measures beyond lighting systems and HVAC controls?

Research and case studies are needed to help identify broader sets of measures with commercially viable financial returns and to determine the conditions that will make other measures technologically and commercially viable in a typical building retrofit.

Retrofit Diagnostic Tool

Evidence from the Empire State Building retrofit suggests that without proper planning it will be difficult to realize energy and carbon reductions that pay back initial investments in a timely manner (i.e., NPV positive). For energy savings to adequately compensate for initial capital investments, a retrofit must typically be preformed during the time when the building would replace major systems and components like windows, lighting, and HVAC. Aligning a building's replacement cycle and an energy efficiency retrofit requires planning, particularly if a large amount of the 75 billion square feet of commercial buildings in the U.S. are to receive energy efficiency retrofits in the future.

A diagnostic tool that could determine when a building is “ripe for retrofit” or ready for other types of energy efficiency improvements like retro-commissioning or tune-ups would improve the industry's ability and effectiveness in planning retrofits across the building stock. Such a tool could help the government and many other large building owners determine how to allocate billions of dollars of capital devoted to energy efficiency retrofits—identifying when and where money should be allocated to bring about the greatest financial returns and cheapest carbon reductions.

Optimizing the Empire State Building Retrofit Process

The process of identifying, evaluating and choosing energy efficiency measures for the Empire State Building took over nine months; typical energy efficiency retrofit recommendations take 2-3 months. Many unique project elements contributed to the length of time needed to finalize a set of energy efficiency measures for the Empire State Building. These unique elements included:

  • Size of the building and diverse tenant profile;
  • Documentation of process to help other owners and ESCOs produce similar retrofits;
  • Collaboration and coordination among a project team took that included the building owner, the property management firm, the ESCO, the sustainability advisor, and select tenants;
  • Modeling of the energy use of the building and the reduction potential of energy efficiency measures using eQUEST; and
  • Evaluation of efficiency measures to reduce energy use in tenant space, and not just in the base building.

Many of these elements contributed to the project's ability to achieve savings that are more than twice that of typical commercial building energy efficiency retrofits. However, to make the Empire State Building process replicable, the process needs to be streamlined. The development of a streamlined process complemented by a set of tools to more quickly identify and evaluate efficiency measures would improve the likelihood that other energy efficiency retrofits could replicate the savings that were identified in the Empire State Building.

What Do You Think…

This list of research topics is a work in progress, and we are interested in hearing input on research and projects that are addressing these topics or other topics that are critical to energy efficiency retrofits in existing buildings. Please send your comments on these issues to As we receive comments on these and other relevant research topics, we will update this site.

1. Hopper, Nicole, Charles Goldman, Jennifer McWilliams, Dave Birr and Kate McMordie Stoughton, 2005. “Public and Institutional Markets for ESCO Services: Comparing Programs, Practices and Performance” Lawrence Berkeley National Laboratory: LBNL-55002, Berkeley, CA, March.

2. Goldman, C., J. Osborn, N. Hopper, and T. Singer, 2002. “Market Trends in the U.S. ESCO Industry: Results from the NAESCO Database Project” Lawrence Berkeley National Laboratory: LBNL-49601, Berkeley, CA, May.