Evaluating the Energy-Saving Effect of Refrigerator Energy Efficiency Label Revision: An Interrupted Time Series Analysis

Evaluating the net energy-saving effect of a mandatory energy efficiency labeling system implemented uniformly at a national scale remains a persistent challenge in policy quantification. Household refrigerators in China have been subject to mandatory energy efficiency labeling since 2005, with the third revision enacted in 2016, tightening the Grade 1 efficiency threshold by approximately 40%. Because the policy was rolled out simultaneously nationwide, no untreated control group exists, rendering conventional difference-in-differences approaches inapplicable and impeding the causal attribution of energy savings to the labeling system. This study employs an interrupted time series (ITS) design, with the 2016 revision designated as the policy breakpoint, to estimate the net effect of the label update on refrigerator energy consumption. Using a segmented linear regression model with Newey–West HAC robust standard errors (lag = 1), the fully adjusted specification identifies a statistically significant negative immediate change of approximately 0.069 kWh in daily energy consumption at the policy implementation point (p < 0.001), although the estimated magnitude is sensitive to the model specification. The flow-based cumulative electricity saving associated with the 2016–2025 period is estimated at 4.84 billion kWh, equivalent to 1.49 million tonnes of coal equivalent and a CO2 emission reduction of 4.31 million tonnes. The findings provide conditional evidence that the label revision was associated with lower refrigerator energy consumption and improved product-level energy performance.