CFR›Title 10›Chapter II›Part 431›Subpart D ContainsSections 431.71–431.72; Subject groups Energy Conservation Standards–Test ProceduresCorpusDaily eCFRDisplayed edition2026-05-07Last updated2026-05-07 Subpart D—Commercial Warm Air Furnaces Contents 431.71 § 431.71 Purpose and scope. 431.72 § 431.72 Definitions concerning commercial warm air furnaces. Energy Conservation Standards Energy Conservation Standards Section 431.77; Appendices A–B Test Procedures Test Procedures Sections 431.75–431.76 Source69 FR 61939, Oct. 21, 2004, unless otherwise noted. Previous C Subpart C—Commercial Refrigerators, Freezers and Refrigerator-Freezers Next E Subpart E—Commercial Packaged Boilers