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Leading Example for Energy Efficiency

Retrofitting America's Favorite Skyscraper

The Empire State Building, a Leading Example for Energy Efficiency

Molly Miller, Rocky Mountain Institute

When you gaze out over the vast canyons of Manhattan from the 86th or 102nd floors of the observatories of the Empire State Building (ESB), you are looking at one of the greenest cities in the United States. New York City's per capita emissions are a third of the national average because of public transit use, density, and smaller residences. New York also vows to reduce current carbon emissions by 30 percent by 2030.

And, if the Empire State Building—built in just over a year and at that time the highest building in the world—embodies the ambition of New York, then it only makes sense for it to be going green now, too as part of its more than $500 million Empire State ReBuilding program. Such was the visionary thinking when the owners of the building took a planned capital improvement renovation to a new level by asking a team of experts including Johnson Controls, Jones Lang LaSalle, and Rocky Mountain Institute convened by the Clinton Climate Initiative (CCI) to recommend sustainability measures that could be incorporated during the planned renovations.

New York City at night

"We have a very deep commitment to sustainability," says Tony Malkin, of the Empire State Building Company. "Without applying sustainable practices in all aspects of our businesses and lives, we will greatly harm our future."

The renovations will let building ownership offer state-of-the-art office amenities in a historic building, and with the team's recommendations, they have the potential to greatly reduce both energy use and carbon emissions. While retrofits typically reduce energy consumption by 10–20 percent, the team proposed an integrated approach to realize savings of almost 40 percent.

To date, few, if any, examples of great pre-war multitenant building retrofits that achieve these standards exist, and the ESB project offers a practical model for other building owners to replicate. Setting this precedent is especially important now as nearly 75 percent of the U.S. commercial building stock is at least 20 years. Working on the Empire State Building to create an exemplary building retrofit project for the rest of the world to replicate came about in large part due to the Clinton Climate Initiative and the launch of their Energy Efficiency Building Retrofit Program in 2007.

"Historically, improvements in existing buildings are made on an ad hoc basis," says Kathy Baczko, New York City director of CCI. "However, so much more energy efficiency and savings can be obtained by taking a whole-building approach, when integrated solutions and blended savings bring long-term benefits. Building owners and operators everywhere should be inspired by this icon of American architecture becoming an example of innovation in building management."

"The idea that the Empire State Building would undergo a green retrofit is immensely inspiring to building owners across the board, whether it's in New York or in any other city, because the Empire State has always been the signature building of New York," adds Carol Willis, founder, director, and curator of the Skyscraper Museum.

The 102-story Art Deco skyscraper at the intersection of Fifth Avenue and West 34th Street has been named by the American Society of Civil Engineers as one of the Seven Wonders of the Modern World. The building and its ground floor interior are designated landmarks of the New York City Landmarks Preservation Commission, and it was designated as a National Historic Landmark in 1986.

"This building is a great example of the right kind of building to retrofit," says Caroline Fluhrer, a consultant with RMI's Built Environment Team. "The fact that it is an iconic building that is going to be around for a long time to come means it makes sense to invest in it. And the fact that it could be coordinated with a major capital improvement project made it really cost-effective.

The capital improvement plan, for example, called for resealing all the windows so they open and close properly. "If you are going to be disturbing tenants and moving them around anyway to work on windows, you might as well put in new energy-efficient windows," explains Caroline.

Wendy Fok, an architect with Jones Lang LaSalle, who worked with RMI and the rest of the team on the ESB recommendations, explains the process for retrofitting the Empire State Building's 6,514 operable windows for energy efficiency: "We use the frames, remove the sashes, reuse the glass, clean it. But between the glass, you'll have an intermediate material which is actually a low emissivity (low-E) film, so even though they call it a triple glazed window, it's actually reusing the existing glazing and inserting a (low-E) film between the two pieces."

The air-handling units offer another example of how the team's recommendations capitalized on the pre-existing capital improvement plan. The team recommended that instead of replacing old units with the same models, as was the practice, ESB should replace them with variable speed fan units when they wear out. While the cost would be marginally higher, the energy efficiency achieved by regulating fan speed by temperature would be much greater and ESB would only need two units per floor instead of the four units per floor they have installed in the past.

The ESB Retrofit Team

Partners on the project included Johnson Controls, Inc. (JCI) as the preferred energy service company (ESCO), Jones Lang LaSalle (JLL) as the project manager, Rocky Mountain Institute as the peer reviewer and sustainability experts, and the Clinton Climate Initiative as a resource and advisor.

"It really was a collaboration," says Caroline. "We work with others all the time, but we truly worked as a team. It was challenging but instilled a lot more confidence in the owner. When several world-renowned groups come to the same conclusion, it makes it easier to move forward."

Key Findings and Recommendations

The project kicked off in February of 2008. Collaborative team activities took place over a six-month period between April and November of 2008. At the conclusion of the seven-month project development process, the team found that at current energy costs, ESB could cost-effectively reduce energy use by 38 percent and save 105,000 metric tons of carbon dioxide over the next 15 years. Achieving an energy reduction greater than 38 percent appears to be cost-prohibitive, given current economic conditions.

To achieve these results, ESB would need to implement eight key projects or measures. The recommended measures also reduce cooling load requirements by 33 percent (1,600 tons) and peak electrical demand by 3.5 megawatts, benefitting both the building and the utility. The measures also improve indoor environmental quality for tenants by way of enhanced thermal comfort from better windows, radiative barriers, and superior controls; they improve indoor air quality through tenant demand-controlled ventilation; and they create better lighting conditions that coordinate ambient and task lighting. The measures include projects related to:

  • Direct Digital Controls (DDC),
  • Tenant Lighting, Daylighting, and Plugs,
  • Variable Air Volume (VAV) Air-Handling Units (AHUs),
  • Retrofit Chiller Plant,
  • Building Windows,
  • Tenant Energy Management Program,
  • Radiative Barrier, and
  • Tenant Demand Control Ventilation (DCV).

Tenant Design

The team has identified three key programs to influence tenant energy use: the tenant pre-built program, tenant design guidelines, and a tenant energy management program. Nearly 40 percent of tenant space will turnover in the next fours years, so aggressive guidelines are needed immediately. The team's proposed green pre-built design will save $0.70–0.90 per square foot in operating costs annually for an additional cost of $6 per square foot and help ESB demonstrate design principles for all tenants to adopt. Design guidelines, based on this pre-built program, will provide green ESB standards. Tenants can verify the technical and economic validity of the recommendations by using a financial decision-making tool the team created specifically for ESB. For the tenant energy management program, ESB will begin sub-metering all tenant spaces and manage a feedback/reporting system to inform tenants about their energy use. This program will also help tenants with their own carbon reporting efforts.

Tenant Pre-Built Space

The ESB team designed a space on the 42nd floor (currently under construction) for the Empire State Building to use in marketing space to prospective tenants. Key design features include a low-pressure drop HVAC system, an indirect layered lighting system (ambient–task–accent lighting), new high-performance glazing, light shelves and blinds, and local, high-recycled content construction materials.

Next Steps

The ESB team is in the process of evaluating all the recommendations for increasing energy efficiency and lowering carbon emissions to determine which measures will be incorporated during the renovations. Regardless of the measures adopted, RMI hopes other building owners can use the analysis and recommendations to replicate the process when retrofitting buildings.

"There is further work to be done to capture the lessons learned, systematize the process and disseminate the results to a broad audience," says RMI Vice President Stephen Doig, who consulted on the project. According to Stephen, some of the lessons from the project include:

"Carrying out retrofits in sync with the normal upgrades to the building makes many more options economically possible. Second, there is a natural tension between maximizing investment returns and maximizing carbon dioxide reduction.  It is important to acknowledge that this tension exists and consider funding mechanisms that provide incentives to achieve the maximum efficiency improvement in an economically viable manner. The work also made clear that, in order to deliver real reductions, owners, ESCOs, tenants and building managers need to be engaged and incented by the process. We were fortunate in our project that was the case, and it needs to become the norm in the future. Finally, we learned that we need to make our approach replicable so it can be widely adopted. "

"From the larger dissemination point of view, I think the most exciting thing is the fact that the Clinton Climate Initiative brings us this platform of the 40 largest cities of the world with a pretty substantive existing building stock comprised largely of commercial office buildings," says Aalok Deshmukh, who worked as RMI's project manager on the ESB recommendations.

"All portfolio managers and real estate owners to some extent have been concerned with energy efficiency, and they've done small things," says Clay Nesler, VP of Global Energy and Sustainability at Johnson Controls. "What this project is going to show is that it actually makes sense to make large and significant energy efficiency improvements, not the 5 to 10 percent type things, but the 20 to 30 percent and more type of improvements, and that there is a business case for doing so."

The Empire State Building retrofit offers a glimpse of the kind of future that is possible for our buildings and cities.

As Carol Willis puts it, "The Empire State Building is the best place to go in order to see the city of New York and the lay of the land as you look out towards the continent or towards the ocean…The Empire State Building stands in this kind of exceptionalism that hopefully will never be compromised."

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