Japan made the best appliance on sale the legal benchmark for every maker

Japan had efficiency standards for fridges, cars and air conditioners since 1980, but they were negotiated with industry, rarely revised, and changed little. When the 1997 Kyoto Protocol committed Japan to cut emissions 6% below 1990 levels, METI needed faster progress. The 1998 revision of the Act on the Rational Use of Energy introduced the Top Runner approach: the most efficient product on the market at standard-setting time becomes the baseline, extended by anticipated technology gains into a target for a year typically four to eight years ahead.

Two design choices made it workable. First, compliance is measured on each manufacturer's shipment-weighted average efficiency, so firms could keep selling a diverse model line — including products that individually fail — as long as the mix improved by the target year. Second, enforcement runs on reputation: METI issues recommendations, publicizes non-compliance, and only then can order penalties. The program started with 9 products in 1998 and grew to 23 categories, covering products that account for more than 70% of Japan's residential electricity use.

The results beat the targets everywhere: room air conditioners improved efficiency 66.1%, computers cut energy use 69.2%, refrigerators 30.5%, and gasoline cars gained 22.8% in km per litre. Required improvements ranged from 16% to 80%, and all were achieved. No producer has ever been publicly named as non-compliant. The OECD estimated the program cut energy use about 8% in households and 5% in road transport.

Make the best product on sale the legal floor

Benchmarking to the best product on sale made every target provably achievable — the technology already existed in the market.

Weighted-average compliance let firms cross-subsidize within their line, keeping product diversity while pulling the whole market up.

Name-and-shame enforcement proved stronger than fines in a concentrated, reputation-sensitive industry.

Manufacturers sat on the standard-setting committees, so they helped write targets they then worked to beat.

Anchor a standard to the best that already exists and grade firms on their whole product mix: laggards must catch up, leaders profit, and nobody can call the target unproven.

The program still runs, with standards revised as each target year arrives, and it expanded from appliances into vehicles, transformers, windows and building insulation. Because the rules bind importers too, foreign makers selling in Japan had to meet them. The weighted-average logic echoes in fuel-economy rules elsewhere, and the UN and OECD have studied Top Runner as a template for efficiency policy.