### Question
What does energy efficiency mean?


### Answer
**Energy efficiency** has the following meaning in *42 U.S.C. § 6291*:

> the ratio of the useful output of services from a consumer product to the energy use of such product, determined in accordance with test procedures under section 6293 of this title

#### Citation:
  - *42 U.S.C. § 6291*
  - Heading: **CHAPTER 76-AGE DISCRIMINATION IN FEDERALLY ASSISTED PROGRAMS > SUBCHAPTER III-IMPROVING ENERGY EFFICIENCY > Part A-Energy Conservation Program for Consumer Products Other Than Automobiles**

