### Question
What is the definition of advanced main air circulating fan?


### Answer
The definition of **advanced main air circulating fan** is as follows in *26 U.S.C. § 25C*:

> a fan used in a natural gas, propane, or oil furnace and which has an annual electricity use of no more than 2 percent of the total annual energy use of the furnace (as determined in the standard Department of Energy test procedures)

#### Citation:
  - *26 U.S.C. § 25C*
  - Heading: **Subtitle A-Income Taxes > CHAPTER 1-NORMAL TAXES AND SURTAXES > Subchapter A-Determination of Tax Liability > PART IV-CREDITS AGAINST TAX > Subpart A-Nonrefundable Personal Credits**

