About
ASAP

Room Air Conditioners

Last Updated: June 2010
See the federal standards main page to view current status

THE PRODUCT: Room air conditioners are encased AC units designed primarily for mounting in a window or through a wall. They are constructed to deliver conditioned air into a room without the use of ducts or with very short ducts. Room AC units have their own source of refrigerant and dehumidification as well as a mechanism for circulating or filtering the air, and may also include mechanisms for ventilation and heating (ASHRAE 2004).

POTENTIAL STANDARD: Room air conditioners were regulated by several states in the 1970s and 1980s and became federally regulated in 1987. The standard varies as a function of cooling capacity and other features, but for the most common type of unit (an 8,000–13,999 Btu/hour unit with side-vents) the 1987 law required an efficiency of 9.0 EER, effective 1990. In 1997, DOE published the most recent standard for room air conditioners, which became effective October 2000. For the most common unit, the EER must be at least 9.8. To qualify for an ENERGY STAR label, room air conditions must meet an EER of at least 10.8. As of 2007, market share for ENERGY STAR-qualified room air conditioners was 50% (EPA 2009a). DOE is required to publish a new standard in 2011, which will become effective in 2014. Since a large portion of the market already meets the ENERGY STAR specification, the current ENERGY STAR level is probably the lower bound for the next standard. Such a standard would save 35 TWh (about .4 quads of primary energy) cumulatively by 2030 and generate $1.5 billion in net present value savings.

KEY FACTS: On average, about 6 million room AC units are sold in the United States each year. 26% of all households have at least one room AC unit (around 50% of these households have two or more) and approximately 20% of all room AC units are over ten years old (EIA 2008a). With the typical room AC unit consuming around 900 kWh/yr, there is potential for significant savings from efficiency improvements. The overall efficiency of room air conditioners can be increased by improving the efficiency of three design elements: motor efficiency (fan and evaporator/compressor motors); refrigerant cycle efficiency, which involves increasing the heat transfer surface in order to minimize the difference between the refrigerant saturation temperature and the air temperature; and air circuit efficiency, which involves minimizing the pressure drop across the heat transfer surface, which reduces the load on the fan motor (ASHRAE 2004).

• Federal Documentation (DOE Web site)

Update
On May 20, 2010, DOE issued analytical results for stakeholders whom are negotiating potential energy conservation standards for room air conditioners. (June 2010)