; no reduction in standard Section 45L(c) is amended by amending paragraph (3) to read as follows: (3) a unit which meets the requirements established by the Administrator of the Environmental Protection Agency under the Energy Star Labeled Homes program and, in the case of a manufactured home, which conforms to Federal Manufactured Home Construction and Safety Standards (part 3280 of title 24, Code of Federal Regulations). . (2) Units constructed in accordance with 2018 IECC standards Section 45L(c), as amended by paragraph (1), is further amended by striking or at the end of paragraph (2), by striking the period at the end of paragraph (3) and inserting , or , and by adding at the end the following new paragraph: (4) certified— (A) to have a level of annual energy consumption which is at least 15 percent below the annual level of energy consumption of a comparable dwelling unit— (i) which is constructed in accordance with the standards of chapter 4 of the 2018 IECC (without taking into account on-site energy generation), and (ii) which meets the requirements described in paragraph (1)(A)(ii), and (B) to have building envelope component improvements account for at least 1/5 of such 15 percent. . (3) Conforming amendments (A) Section 45L(c)(2) is amended by inserting or (4) after paragraph (1) . (B) Section 45L(a)(2)(A) is amended by striking or (2) and inserting , (2), or (4) . (C) Section 45L(b) is amended by adding at the end the following: (5) 2018 IECC The term 2018 IECC means the 2018 International Energy Conservation Code, as such Code (including supplements) is in effect on November 1, 2018. . (e) Effective dates The amendments made by this section shall apply to dwelling units acquired after December 31, 2020. 305. Modifications to income exclusion for conservation subsidies (a) In general Section 136(a) is amended— (1) by striking any subsidy provided and inserting any subsidy— (1) provided , (2) by striking the period at the end and inserting a comma, and (3) by adding at the end the following new