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Open Access Publications from the University of California

Lost in translation: Overcoming divergent seasonal performance metrics to strengthen air conditioner energy-efficiency policies


With increasing global uptake of variable-speed (inverter-driven) air conditioners (ACs), the globally uniform energy-efficiency ratio (EER) metric has given way to various region-specific part-load and seasonal performance AC metrics in many markets. As a result, policymakers around the world lack comparative data that might help them create more effective AC efficiency market-transformation programs. To help fill this gap, this paper explores relationships between the room AC efficiency performance metrics of different regions—including China, the European Union, India, Japan, South Korea, and the United States—using performance data for split room AC models. We use these interregional conversion relationships to estimate the performance of >6000 AC models, including reversible heat pumps, in efficiency metrics used in the six economies as well as the International Organization for Standardization (ISO) 16,358 metric. Our results suggest a way to identify the potential for improving AC efficiency policies in regional markets. The most efficient models sold in each region and worldwide typically are more efficient than the most efficient level recognized by regional energy standards and labeling programs. This information could help policymakers evaluate and improve their AC efficiency market-transformation programs to align with the globally best-available technology.

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