Energy class (EU label)
The A to G letter rating on the mandatory EU energy label, A being the most efficient.
The EU energy label rates appliances on an A (most efficient) to G (least efficient) scale, rescaled in 2021 so that no product starts as an A+++ any more, headroom was deliberately left at the top for future efficiency gains. The scale is specific to each appliance category: a washing machine's A and a dishwasher's A represent different absolute energy-use thresholds, so you can only compare energy class meaningfully within the same category, which is exactly how our compare tool treats it.