### Question
How is the "auxiliary power unit" defined?


### Answer
The term **auxiliary power unit** is defined in *42 U.S.C. § 16104* as follows -

> an integrated system that—


(A) provides heat, air conditioning, engine warming, or electricity to components on a heavy-duty vehicle

#### Citation:
  - *42 U.S.C. § 16104*
  - Heading: **CHAPTER 149-NATIONAL ENERGY POLICY AND PROGRAMS > SUBCHAPTER VII-VEHICLES AND FUELS > Part D-Miscellaneous**

