It’s Easy Being Green: The United States’ Tallest Green Building?

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Here’s an iconic example of the growing movement to weatherize commercial buildings and improve their energy efficiency: A consortium of nonprofits and building owners led by the Rocky Mountain Institute announced plans on April 8 to retrofit New York City’s (and once the world’s) tallest building: the 102-story Empire State Building. The $20 million project aims to reduce the skyscraper’s energy use by 38 percent a year by 2013 at an annual savings of $4.4 million. And while the retrofit measures will be specifically designed for the building, “the energy-efficiency improvements are meant to serve as a model for other office buildings around the world,” says The New York Times.

According the Times, over three-quarters of New York City’s carbon emissions (78 percent) come from supplying energy for commercial and residential buildings. The Empire State Building’s retrofit aims to prevent the release of 105,000 metric tons of CO2 annually—the same amount Washington, D.C puts out in nearly 10 days.

For the last year, the Rocky Mountain Institute worked in partnership with the Clinton Climate Initiative, Johnson Controls, Inc., and Jones Lang LaSalle to study the building’s energy use. From their research, the team identified the eight best efficiency returns. Since lighting, cooling, and heating represent the highest energy costs of the building, many of the measures are targeted at those. Here’s what they came up with.

  • Window insulation: This would include the refurbishment of glass windows, using existing glass and sashes to create triple-glazed insulated panels with new components that dramatically reduce both summer heat load and winter heat loss.
  • Radiator insulation: Added insulation behind radiators would be used to reduce heat loss and more efficiently heat the building perimeter.
  • Tenant lighting improvements: Introduction of improved lighting designs, controls, and plug load occupancy sensors in common areas and tenant spaces to reduce electricity costs and cooling loads.
  • Air handler replacements: Replacement of air handling units—devices used to condition and circulate air as part of a heating, ventilating, and air-conditioning system, or HVAC—with variable frequency drive fans to allow increased energy efficiency in operation while improving comfort for individual tenants.
  • Chiller/air-conditioning plant retrofit: Reuse of existing chiller shells—chillers are used in AC units to cool and dehumidify air—while removing and replacing “guts” to improve chiller efficiency and controllability, including the introduction of variable frequency drives.
  • Whole-building control system upgrade: Upgrade of existing building control system to optimize HVAC operation, as well as to provide more detailed submetering information.
  • Ventilation control upgrade: Introduction of demand control ventilation in occupied spaces to improve air quality and reduce energy required to condition outside air.
  • Tenant energy management systems: Introduction of individualized, web-based power usage systems for each tenant to allow more efficient management of power usage.

Moreover, other skyscrapers are following suit, discovering that green renovations pay for themselves with higher income from rent, lower utilities, and less maintenance. The Sears Tower, another symbol of American ingenuity and ambition, announced in February that it also had plans to achieve a Leadership in Energy and Environment Design standard similar to what the Empire State Building has set out for itself. A spokesman for the tower said the following:

“The Sears Tower is exploring ways to reduce energy and water usage at the building that could help the building achieve LEED certification. Improvements to lighting systems, mechanical systems, and elevator systems are all being investigated. Other initiatives include looking at renewable energies, such as solar and wind power at roof level, and the installation of green roofs, which could include the tallest green roof in the U.S.”

Both of these initiatives are on to something: Sustainable retrofits can be a good investment for building owners. Their upfront cost can be rapidly repaid and ultimately result in savings. Of the $20 million to be spent on the Empire State Building project, $13.2 million would have spent as general maintenance anyway. Typical retrofits can increase building efficiency by 30 percent, reducing utility bills and paying for themselves in one to two years. The Department of Energy estimates that energy utilities cost U.S. buildings $369 billion in 2005. Building owners can cut that cost by 50 percent or more by retrofitting and applying energy efficient technologies to properties.

The Empire State Building is one of many buildings worldwide improving its energy efficiency and helps herald a new era of sustainability that pays. The building’s retrofit template will be replicable, cost efficient, and use existing technology while hopefully providing inspiration and best practices for other building owners eyeing a sustainable new look for their property.

You can check out the progress of the project at, which was developed to make the design and performance of the project public.

Read more articles from the "It’s Easy Being Green" series