# Federal Register #2026-20517

DOE withdraws the Thermal Efficiency Two test procedure for commercial warm air furnaces

**Buyer:** U.S. Department of Energy (DOE)
**Posted:** October 07, 2026
**Identifier:** 2026-20517

The U.S. Department of Energy issued a final rule changing the test procedures for commercial warm air furnaces.
- **Government buyer:** U.S. Department of Energy (DOE), Office of Critical Minerals and Energy Innovation.
- **Regulatory action:** Withdraws appendix B, the Thermal Efficiency Two test procedure; commercial warm air furnaces remain subject to appendix A, the Thermal Efficiency test procedure.
- **Rationale:** DOE found that the uncertain improvement in how representative appendix B was did not justify its likely additional testing burden.
- **Manufacturers named:** AAON, JCI, Rheem, and Trane (also referenced as Trane Technologies). AHRI is also mentioned as an industry association, not as a manufacturer.
- **Procurement scope:** This is a regulatory action, not a solicitation for products or services. No quantities, part numbers, or purchase requirements are listed.

### Description

The Department of Energy is withdrawing appendix B, the test procedure for measuring the energy efficiency of commercial warm air furnaces using the Thermal Efficiency Two method. DOE determined that the uncertain increase in representativeness from appendix B does not outweigh its likely increase in burden. Commercial warm air furnaces remain subject to the testing requirements in appendix A, the Thermal Efficiency method. The rule takes effect December 7, 2026.

[View original listing](https://www.federalregister.gov/documents/2026/10/07/2026-20517/energy-conservation-program-test-procedures-for-commercial-warm-air-furnaces)