The National Appliance Energy Conservation Act (NAECA) of 1987 established minimum energy-efficiency standards for room air conditioners, which became effective on January 1, 1990. The 1990 minimum energy-efficiency ratios (EER) range from 8.0 to 9.0 (Btu/h)/W (2.34 to 2.64 W/W). As required by NAECA, the Department of Energy (DOE) must also consider amending the room air conditioner standards that went into effect in 1990. As a result, the DOE issued a Notice of Proposed Rulemaking (NOPR) in March 1994 proposing new energy-efficiency standards for several products including room air conditioners. DOE received an extensive number of comments in response to the updated standards that were proposed. A reanalysis was conducted incorporating these comments, resulting in revised estimates of the cost and efficiency increases for more efficient room air conditioner designs. This paper describes the cost-efficiency analysis of design options carried out in support of DOE's effort to revise the energy-efficiency standards that were proposed for room air conditioners in March 1994. The analysis shows that for the most popular classes of room air conditioners (classes without reverse cycle, with louvered sides, and with capacities ranging from less than 6000 to 20,000 Btu/h [1758 to 5860 W]), EERs of approximately 10.0 (Btu/h)/W (2.93 W/W) can be achieved by incorporating commonly used technologies, such as high-efficiency rotary compressors, grooved refrigerant tubing, slit-type fins, subcoolers, and permanent split capacitor fan motors. Even greater increases in efficiency can be realized with brushless permanent magnet fan motors, enlarged heat exchanger coils, and variable-speed compressors.

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