The Department of Energy (DOE) proposed new efficiency standards that would slash commercial rooftop air conditioner energy use by about 30%. The proposed standards would achieve the largest national energy savings of any standard ever issued by the U.S. Department of Energy.
“DOE’s new standards are a breath of cool air for businesses since air conditioners account for about 10 percent of a typical commercial building’s electricity cost,” said Steve Nadel, executive director of the American Council for an Energy-Efficient Economy. “The new standards will drive innovative, energy-efficient air conditioners into buildings across America, not only saving businesses money, but also reducing electricity demand and environmental emissions.”
"Commercial cooling is a big part of the electricity load in many parts of California,” said Vincent Davis, senior director of energy efficiency at Pacific Gas and Electric Company (PG&E). “Working through our efficiency programs, PG&E and the other California utilities have encouraged installation of high efficiency commercial cooling systems. These proposed new national standards will help further drive energy savings for customers."
DOE estimates that over the lifetime of units sold over thirty years, the proposed standards would save businesses between $16 and $50 billion and reduce electricity consumption by about 1.3 trillion kilowatt-hours, or enough energy to cool all the commercial buildings in the U.S. for 7 years. The new standards would net a typical building owner between $3,500 and $16,500 over the life of a single commercial rooftop air conditioner. Overall savings will often be higher since most buildings have multiple units. For example, a big-box store can have more than 20 rooftop air conditioners.
Rooftop air conditioners are commonly used in low-rise buildings such as schools, restaurants, big-box stores, and small office buildings. They cool about half of the total commercial floor space in the United States. (Most of the other half is cooled by chilled water systems, residential-type central air conditioners, or individual air conditioners mounted in windows or external walls.)
The current efficiency standards for rooftop air conditioners measure efficiency at full capacity despite the fact that air conditioners rarely operate at that level except on the hottest days. The new proposed standards are instead based on a metric called IEER (integrated energy efficiency ratio) which captures efficiency at 25, 50, 75, and 100% of full capacity and better reflects real-world performance. Typical new rooftop air conditioners that just meet the commercial building energy code have efficiency levels of about 9.5 to 11.5. However, DOE’s High Performance Rooftop Unit Challenge has helped spur several manufacturers to develop and bring to market high-efficiency rooftop air conditioners. Equipment on the market today achieves IEER levels as high as 21. Today’s proposed standards would set minimum efficiency levels of 12.3 to 14.8 depending on equipment type and capacity.
“Energy efficiency standards covering a range of products have been one of America’s most successful policies for meeting the nation’s energy needs,” said Andrew deLaski, executive director of the Appliance Standards Awareness Project. “Thanks to already existing standards, U.S. electricity use will be about 14% lower in 2035. The new commercial AC standards along with other new standards completed this year will add to that record of achievement.”
In 2013, President Obama established a goal of reducing CO2 emissions by 3 billion metric tons by 2030 through efficiency standards. DOE is now about 70% of the way towards the President’s goal. DOE is scheduled to publish a final rule for rooftop air conditioners by the end of 2015.