[Code of Federal Regulations] [Title 10, Volume 3] [Revised as of January 1, 2006] From the U.S. Government Printing Office via GPO Access [CITE: 10CFR431.72] [Page 414-415] TITLE 10--ENERGY CHAPTER II--DEPARTMENT OF ENERGY PART 431_ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT--Table of Contents Subpart D_Commercial Warm Air Furnaces Sec. 431.72 Definitions concerning commercial warm air furnaces. The following definitions apply for purposes of this subpart D, and of subparts J through M of this part. Any words or terms not defined in this Section or elsewhere in this Part shall be [[Page 415]] defined as provided in Section 340 of the Act. Commercial warm air furnace means a warm air furnace that is industrial equipment, and that has a capacity (rated maximum input) of 225,000 Btu per hour or more. Thermal efficiency for a commercial warm air furnace equals 100 percent minus percent flue loss determined using test procedures prescribed under Sec. 431.76. Warm air furnace means a self-contained oil-fired or gas-fired furnace designed to supply heated air through ducts to spaces that require it and includes combination warm air furnace/electric air conditioning units but does not include unit heaters and duct furnaces. Test Procedures