of heat output to energy input, with details specified in applicable Department of Energy test procedures. For gas commercial heat pump water heaters, until there is a Department of Energy test procedure, American National Standards Institute and American Society of Heating, Refrigerating and Air-Conditioning Engineers Standard 118.1 shall be used. For gas commercial heat pumps, until there is a Department of Energy test procedure, American National Standards Standard Z21.40.4 shall be used. For industrial heat pumps, until there is a Department of Energy test procedure, manufacturers may use their own tests, provided they publicly post the test conditions and assumptions they used in developing their stated Coefficient of Performance values. (i) Special rules For purposes of this section: (1) In general Rules similar to the rules of subsections (c), (d), and (e) of section 52 shall apply. (2) Controlled group (A) In general All persons treated as a single employer under subsection (a) or (b) of section 52 or subsection (m) or (o) of section 414 shall be treated as a single producer. (B) Inclusion of foreign corporations For purposes of subparagraph (A), in applying subsections (a) and (b) of section 52 to this section, section 1563 shall be applied without regard to subsection (b)(2)(C) thereof. (3) Verification No amount shall be allowed as a credit under subsection (a) with respect to which the taxpayer has not submitted such information or certification as the Secretary, in consultation with the Secretary of Energy, determines necessary. (4) Production in United States The requirement for production in the United States in section (c) does not take effect until January 1, 2024. . (b) Clerical amendment The table of sections for subpart D of part IV of subchapter A of chapter 1 is further amended by adding after the item relating to section 45V the following new item: Sec. 45W. Manufacturer credit for high-efficiency heat pumps and heat pump water heaters. . 210. Other authorizations of appropriations (a)