i do not know about the US Energy Star rating, in europe we have this: https://en.wikipedia.org/wiki/...
This is required and very useful. Most people DO look at then, specially on more expensive or consuming appliances. It keeps being improved and allows one to see how much energy or water they use per year. IIRC, newest version even show how much that energy cost in euros, so one can compare several appliances and see how much money one safe by going with a better ratting. Even if more expensive, some pay themselves.
The end result was that junk, consuming appliances quickly disappeared from market, even a uneducated users would look to 2 similar priced appliances, one with rating B and another with rating D, they would choose the B. sometimes simple tune ups from a brand could upgrade the rating, without affecting the price.
Today energy efficiency are publicized by the brands and the even move those energy label to well visible areas, so people can compare