SECTION 4. ELIGIBLE BUILDING

ENVELOPE COMPONENTS

.01 Under ARRTA, an eligible building envelope component for a taxable year beginning after December 31, 2008, is a component that is placed in service on or before February 17, 2009, and is described in section 2.03(1) of this notice or a component that is placed in service after February 17, 2009, and is described below: (1) Insulation Material or System . An insulation material or system (including any vapor retarder or seal to limit infiltration) that—

(a) Is specifically and primarily designed (within the meaning of section 4.03 of this notice) to reduce heat loss or gain of a dwelling unit when installed in or on the dwelling unit; and

(b) Meets the prescriptive criteria for such material or system established by the 2009 IECC, as such Code (including supplements) was in effect on February 17, 2009. (2) Exterior Window, Skylight, or Door . An exterior window, skylight, or door

2009–25 I.R.B. 1097 June 22, 2009