# 10 CFR § 431.72: Definitions concerning commercial warm air furnaces

> Federal · Regulations · In force

URL: https://www.frixlaw.com/law-library/statutes/ecfr-10-431.72

## Section

- **Citation:** 10 CFR § 431.72
- **Heading:** Definitions concerning commercial warm air furnaces
- **Jurisdiction:** Federal
- **Kind:** Regulations
- **Status:** In force
- **Text as of:** September 22, 2026
- **Source:** Publisher's official text
- **Location:** Title 10—Energy > CHAPTER II—DEPARTMENT OF ENERGY > SUBCHAPTER D—ENERGY CONSERVATION > PART 431—ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT > Subpart D—Commercial Warm Air Furnaces

## Text

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 defined as provided in Section 340 of the Act.
Basic model means all commercial warm air furnaces manufactured by one manufacturer within a single equipment class, that have the same nominal input rating and the same primary energy source (e.g. gas or oil) and that do not have any differing physical or functional characteristics that affect energy efficiency.
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 § 431.76.
Thermal efficiency two for a commercial warm air furnace equals 100 percent minus percent flue loss and jacket loss.
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.
[69 FR 61939, Oct. 21, 2004, as amended at 76 FR 12503, Mar. 7, 2011; 78 FR 79598, Dec. 31, 2013; 88 FR 36233, June 2, 2023]

## Nearby sections

- [10 CFR § 431.1 § 431.1 Purpose and scope.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.1.md)
- [10 CFR § 431.2 § 431.2 Definitions.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.2.md)
- [10 CFR § 431.3 § 431.3 Error Correction procedure for energy conservation standards rules.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.3.md)
- [10 CFR § 431.4 § 431.4 Procedures, interpretations, and policies for consideration of new or revised energy conservation standards and test procedures for commercial/industrial equipment.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.4.md)
- [10 CFR § 431.11 § 431.11 Purpose and scope.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.11.md)
- [10 CFR § 431.12 § 431.12 Definitions.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.12.md)
- [10 CFR § 431.61 § 431.61 Purpose and scope.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.61.md)
- [10 CFR § 431.62 § 431.62 Definitions concerning commercial refrigerators, freezers and refrigerator-freezers.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.62.md)
- [10 CFR § 431.71 § 431.71 Purpose and scope.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.71.md)
- [10 CFR § 431.72 § 431.72 Definitions concerning commercial warm air furnaces.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.72.md)
- [10 CFR § 431.81 § 431.81 Purpose and scope.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.81.md)
- [10 CFR § 431.82 § 431.82 Definitions concerning commercial packaged boilers.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.82.md)
- [10 CFR § 431.91 § 431.91 Purpose and scope.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.91.md)
- [10 CFR § 431.92 § 431.92 Definitions concerning commercial air conditioners and heat pumps.](https://www.frixlaw.com/law-library/statutes/ecfr-10-431.92.md)

---

Source: Frix Law Library, https://www.frixlaw.com/law-library/statutes/ecfr-10-431.72. Check the current official text before relying on it. Not legal advice.