"ENERGY STAR does not label clothes dryers because there is little difference in energy use among models." (link)I would look for the most efficient washer option that's in your price range, and pair it up with the same company's dryer, assuming they offer a stackable option. (Or better yet, skip the dryer and use a rack or clothesline.) A good front-loading washer will remove a lot of water from the clothes, making them dry faster.