efficiency descriptor
(22) The term “efficiency descriptor” means the ratio of the useful output to the total energy input, determined using the test procedures prescribed under section 6293 of this title and expressed for the following products in the following terms: (A) For furnaces and direct heating equipment, annual fuel utilization efficiency. (B) For room air conditioners, energy efficiency ratio. (C) For central air conditioning and central air conditioning heat pumps, seasonal energy efficiency ratio. (D) For water heaters, energy factor. (E) For pool heaters, thermal efficiency.