### Question
What does auxiliary power unit mean?


### Answer
**Auxiliary power unit** has the following meaning in *42 U.S.C. § 16104*:

> 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-ENERGY POLICY, 2005 > SUBCHAPTER VII-VEHICLES AND FUELS > Part D-Miscellaneous**

