Although in the past the majority of sustainable construction activity has been focused on new construction, today there is a movement in major cities toward green retrofits in both privately and publicly owned buildings.  According to the United States Green Building Council, a “green retrofit” refers to upgrades to an existing building that improve energy and environmental performance, reduce water use, improve the comfort and quality of the space in terms of natural light, noise, and air quality, and are completed in a way that is financially beneficial to the owner and tenants.  While the continued efforts in sustainable new construction are fruitful, new construction represents only a small portion of the overall building population.  Focusing on green retrofits and sustainable renovations of existing buildings can have a larger impact on the environment.

In the United States, existing buildings account for approximately 73% of electricity consumption and 38% of CO2 emissions.  While it has become common for new buildings in major cities to incorporate a green focus and attempt to obtain LEED certification, there is now a push for existing buildings to obtain LEED certification through green retrofits.  According to the USGBC, the purpose of LEED for existing buildings is to help building owners measure operations, improvements and maintenance on a consistent scale, with the goal of maximizing operational efficiency and minimizing environmental impacts.  As of December 8, 2011, the cumulative total of LEED-certified square footage for existing buildings surpassed the total of LEED-certified square footage for new buildings.

Part of the momentum in the green retrofit movement can be attributed to the C40 Cities Climate Leadership Group that is chaired by New York City Mayor Michael Bloomberg. The group is comprised of 40 major cities across the globe and recognizes the important role that cities play in addressing global climate change. The C40 Group estimates that if every commercial building in New York City implemented a green retrofit, carbon emissions could be reduced by 4 million tons. One recent project that the C40 Group has acknowledged as a model for sustainable climate action is the green retrofit of the Empire State Building.

A little over a year ago, the Empire State Building completed the core components of its green retrofit project. The project was designed to integrate energy efficiency into building upgrades that would cut costs and improve the overall value of the building. With this in mind, the project implemented energy conservation measures including: radiator insulation and steam traps; insulation of windows with transparent coated film and injection of odorless gas fill between window panes; direct digital controls; demand controlled ventilation; chiller plant retrofit; tenant controlled energy management monitoring systems; tenant use of daylighting and efficient lighting and plugs; and variable air volume controlled air handling units. The building was awarded LEED gold certification and is the tallest building in the United States to be LEED certified.

According to the owners, in the first year since the initial upgrades, the Empire State Building has surpassed its projections and exceeded its first year efficiency guarantee by five percent, saving $2.4 million. While the majority of the upgrades have been completed, some of the planned upgrades in the building’s tenant suites will not be finished until tenant contracts expire. Once all of the upgrades are completed, the owners anticipate that the building will save around $4.4 million a year, reduce energy use by 38 percent and cut carbon emissions by 105,000 metric tons over the next 15 years.

JP Morgan has shown a similar commitment to the environment and implemented many of the same energy conservation measures in the green retrofit of its New York City headquarters. The owners estimate that the renovations will cut the building’s electricity consumption in half and save more than a million gallons of water a year because of the installation of efficient draining and filtering systems. Likewise, the 125 Broad Street Tower located in downtown New York City recently underwent a green retrofit and was able to greatly reduce the building’s carbon footprint. The 125 Broad Street tower is one of the first commercial office buildings located in downtown New York City to earn a LEED silver rating for existing buildings. The owners estimate that the green retrofit has reduced the buildings carbon footprint by 6667 tons in just a two year period. In the public sector, universities and landmarks such as the New York City Public Theatre have been leading the way by taking on green retrofit projects of their own.

Moving forward, the hope is that more commercial and public buildings will join the green retrofit movement and implement energy and environmental conservation measures. In addition to having a positive impact on the environment, implementation of green retrofits could create jobs and benefit the economy. According to a study by Pike Research, an energy intelligence and consulting firm, upgrading all of the commercial space that is due for a comprehensive retrofit would require building owners to spend approximately $400 billion on the upgrades.