If the Secretary has prescribed test procedures under section 6314 of this title for any class of covered equipment, he shall prescribe a labeling rule applicable to such class of covered equipment in accordance with the following provisions of this section.

A labeling rule prescribed in accordance with this section shall require that each article of covered equipment which is in the type (or class) of industrial equipment to which such rule applies, discloses by label, the energy efficiency of such article, determined in accordance with test procedures under section 6314 of this title. Such rule may also require that such disclosure include the estimated operating costs and energy use, determined in accordance with test procedures under section 6314 of this title.