Qualified energy efficiency improvements

The term “qualified energy efficiency improvements” means any energy efficient building envelope component, if—

(A) such component is installed in or on a dwelling unit located in the United States and owned and used by the taxpayer as the taxpayer’s principal residence (within the meaning of section 121),

(B) the original use of such component commences with the taxpayer, and

(C) such component reasonably can be expected to remain in use for at least 5 years.

The term “energy efficient building envelope component” means a building envelope component which meets—

(A) in the case of an exterior window or skylight, Energy Star most efficient certification requirements,

(B) in the case of an exterior door, applicable Energy Star requirements, and

(C) in the case of any other component, the prescriptive criteria for such component established by the most recent International Energy Conservation Code standard in effect as of the beginning of the calendar year which is 2 years prior to the calendar year in which such component is placed in service.