SECTION 4. CERTIFICATION

Before a taxpayer may claim the § 179D deduction with respect to property installed on or in a commercial building, the taxpayer must obtain a certification with respect to the property. The certification must be provided by a qualified individual and satisfy the requirements of § 179D(c)(1). A taxpayer is not required to attach the certification to the return on which the deduction is taken. However, § 1.6001–1(a) of the Income Tax Regulations requires that taxpayers maintain such books and records as are sufficient to establish the entitlement to, and amount of, any deduction claimed by the taxpayer. Accordingly, a taxpayer claiming a deduction under § 179D should retain the certification as part of the taxpayer’s records for purposes of § 1.6001–1(a) of the Income Tax Regulations. A certification will be treated as satisfying the requirements of § 179D(c)(1) if the certification contains all of the following:

water, and interior lighting systems. Reductions in any other energy uses, such as receptacles, process loads, refrigeration, cooking, and elevators, are not taken into account in determining whether the 16 ² /3-percent reduction is achieved. (2) Maximum Amount of Deduction . (a) In General . The deduction for the cost of energy efficient building envelope property installed on or in a building shall not exceed the excess (if any) of—

(i) the product of $0.60 and the square footage of the building, over

(ii) the aggregate amount of the § 179D deductions allowed with respect to energy efficient building envelope property installed on or in the building for all prior taxable years.

(b) Application to Multiple Taxpayers . If two or more taxpayers install energy efficient building envelope property on or in the same building, the aggregate amount of the § 179D deductions allowed to all such taxpayers with respect to the building shall not exceed the amount determined under section 2.05(2)(a) of this notice.