In 2021 the EU introduced a new set of energy efficiency scales the original scale being A-G was modified to become A++-F. Now they have introduced a new scale A-F. This has resulted in a lot of confusion because many products are old and the manufacturers have not re-calculated the classes because they consider the products obsolete. Some old products are now branded with the new scale but are still listed on many websites at the old scale. So if a product is A on the old scale it might show E on the box when the item arrives. the product is the same it is just the scale has been re-calculated.
The new scale is aspirational and so at the time of launch was there wasn't a product on the market that was better than a D. Since then there are a limited number of product in the C category but for the majority of products E is the best available on the market (new scale) or A++ under the old scale. If you buy something that is E on the new scale it is still super efficient; the authorities are trying to re-base the products so that the scale will not need changing again.