1. Energy efficient commercial buildings deduction (a) Deduction made permanent Section 179D of the Internal Revenue Code of 1986 is amended by striking subsection (h). (b) Allocations of deductions Paragraph (4) of section 179D(d) of such Code is amended to read as follows: (4) Allocation of deduction for certain property (A) Property held by governments and nonprofits In the case of energy efficient commercial building property installed on or in property owned by a Federal, State, local, or Indian tribal government, or a political subdivision thereof, or by an organization that is described in section 501(c)(3) and exempt from tax under section 501(a), the Secretary shall promulgate a regulation to allow the allocation of the deduction to the person primarily responsible for designing the property in lieu of the owner of such property. Such person shall be treated as the taxpayer for purposes of this section. (B) Allocations to partnerships and S corporations In the case of an allocation of a deduction under this section to a partnership or S corporation, the Secretary shall by regulation or other guidance allow the full benefit of a deduction allocated under this paragraph at the partner or shareholder level. . (c) Low-Income housing exception to basis reduction Subsection (e) of section 179D of such Code is amended by inserting (other than property placed in service in a qualified low-income building (within the meaning of section 42)) after building property . (d) Conforming amendments (1) The heading for section 179D of such Code is amended by inserting and multifamily after commercial . (2) The item in the table of sections for part VI of subchapter B of chapter 1 of such Code relating to section 179D of such Code is amended by inserting and multifamily after commercial . (e) Effective date (1) In general Except as provided by paragraph (2), the amendments made by this section shall apply to property placed in service after December 31, 2017. (2) Exception for permanency The amendment made by subsection