More Good Efficiency News for Rooftop Air Conditioners

The savings for rooftop air conditioners—which cool more than half of commercial floor space in the United States—just keep coming.

The Department of Energy (DOE) recognized six large companies this week for their investments in increasing the efficiency of these rooftop air conditioners by replacing or retrofitting aging, inefficient units with more efficient machinery.

Rooftop air conditioners—commonly used in low-rise buildings such as schools, restaurants, big-box stores and small office buildings—are big energy users. But the upgrades made by the six companies, which include such major retailers as Target and Walmart, will save an estimated 1 trillion BTU in a single year—enough energy savings to offset the annual carbon emissions of about 21,000 homes—while cutting more than $11 million in yearly energy costs.

These investments add to the success story on rooftop air conditioners and demonstrate the large magnitude of savings available from this product category.

Even greater savings are on the way from the largest energy efficiency standards ever issued for commercial rooftop air conditioners last December. Over 30 years, these standards, which go into effect starting in 2018, will save 15 quadrillion BTU, enough energy savings to offset the carbon emissions from more than 120 million U.S. homes for a year.

The standards, a product of negotiations between manufacturers, utilities, consumer and environmental groups (including NRDC) and others, are critical to the president’s goal of reducing carbon pollution by at least 3 billion metric tons by 2030 through efficiency rules for appliances and federal buildings. Cutting the energy use of rooftop air conditioners reduces the need to burn fossil fuels to generate the electricity necessary to power them, which avoids the dangerous carbon emissions fueling climate change. 

The standards build upon the success of programs, such as the High Performance Rooftop Unit Challenge, a performance specification that encouraged U.S. manufacturers to deliver innovative, competitively-priced, energy-saving commercial air conditioners,  and the voluntary Advanced RTU Campaign (ARC), an initiative of DOE’s Better Buildings Alliance and Federal Energy Management Program, ASHRAE, and the Retail Industry Leaders Association to encourage commercial building owners and operators to make their rooftop units more energy efficient. The six companies recognized this week are participants in the ARC campaign.

Since the ARC campaign was launched in 2013, 250 public and private sector organizations have upgraded 59,500 rooftop units, or RTUs, for a total energy savings of 10 trillion BTU and $93 million in cost savings, according to DOE, which offers guidance on when to replace or retrofit rooftop units.

The businesses recognized by DOE are:

  • Arby's Restaurant Group, Inc., which installed 238 high-efficiency rooftop units across 900 stores for an estimated savings of 1.4 million kilowatt hours and $140,000 annually. DOE called it “the most innovative RTU management approach’’ by a participant in the campaign.
  • Giant Tiger Stores Limited achieved an efficiency gain of 63 percent—the largest for a single building rooftop replacement project.
  • Southern California Edison upgraded 4,679 high-efficiency RTUs and 400 advanced RTU control retrofits for an estimated savings of 31 million kWh, worth $4.7 million annually.
  • Target Corporation upgraded 532 RTUs for an estimated savings of 10 million KWh, worth $1 million annually. DOE called it the “most innovative, comprehensive RTU operations approach by a partner for enabling large reductions in installed capacity and includes centralized and optimized control of RTUs.’’
  • Walmart Stores, Inc. upgraded 5,919 RTUs—the highest number of high-efficiency RTU installations—resulting in an estimated savings of 50 million kWh, worth $5 million annually.
  • Whole Foods Market retrofitted 839 advanced control retrofits—the highest number of advanced RTU control retrofits—resulting in an estimated savings of 7.6 million kWh, worth $747,000 annually.

They are just the latest companies to achieve significant energy—and money—savings by investing in more energy efficient rooftop units.

A building's cooling and ventilating energy consumption can be reduced between 20 percent and 50 percent when aging equipment is replaced with high-efficiency units or retrofitted with advanced controls, according to DOE. A building owner can reduce energy costs as much as $3,700 per RTU, nationally potential savings add up to $6.7 billion and 670 trillion BTU annually.

The savings show, once again, how energy efficiency is the cheapest and fastest way to reduce the carbon pollution that drives dangerous climate change while saving us money and reducing other pollution that harms our health.

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