### Question
How does the law define furnace?


### Answer
Under *42 U.S.C. § 6291*, **furnace** is defined as:

> a product which utilizes only single-phase electric current, or single-phase electric current or DC current in conjunction with natural gas, propane, or home heating oil, and which—


(A) is designed to be the principal heating source for the living space of a residence

#### Citation:
  - *42 U.S.C. § 6291*
  - Heading: **CHAPTER 77-ENERGY CONSERVATION > SUBCHAPTER III-IMPROVING ENERGY EFFICIENCY > Part A-Energy Conservation Program for Consumer Products Other Than Automobiles**

