DOE has published a Federal Register final rule establishing energy conservation standards for direct expansion-dedicated outdoor air systems (DX-DOASes) that are of equivalent stringency as the minimum levels specified in the most recent publication of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1 “Energy Standard for Buildings Except Low-Rise Residential Buildings” (ASHRAE 90.1-2019) when tested pursuant to the DOE test procedure for DX-DOASes – which incorporates by reference the most recent applicable industry standard for this equipment. DOE has determined that it lacks clear and convincing evidence to adopt standards more stringent than the levels specified in ASHRAE 90.1-2019.

• The effective date of this rule is January 3, 2023. 
• Compliance with the standards established for DX-DOASes in this final rule is required on and after May 1, 2024.

DOE has published a Federal Register notice publishing a final rule to establish definitions for “direct expansion-dedicated outdoor air systems” (DX- DOASes) and “unitary dedicated outdoor air systems” (unitary DOASes). Unitary DOASes are a category of small, large, and very large commercial package air conditioning and heating equipment under the Energy Policy and Conservation Act, as amended. In addition, DOE is establishing a test procedure to measure the energy efficiency of DX-DOASes, which aligns with the most recent version of the relevant industry consensus test standards for DX-DOASes, with certain minor modifications. Lastly, DOE is adopting supporting definitions, energy efficiency metrics for dehumidification and heating modes, and provisions governing public representations as part of this rulemaking.

• The effective date of this rule is August 26, 2022.
• The incorporation by reference of certain material listed in this rule is approved by the Director of the Federal Register August 26, 2022.
• Representations with respect to energy use or efficiency of direct expansion-dedicated outdoor air systems must be based on testing conducted in accordance with this final rule on or after July 24, 2023.

For the latest information on the planned timing of future DOE regulatory milestones, see the current Office of Management and Budget Unified Agenda of Regulatory and Deregulatory Actions. All planned dates are preliminary and subject to change.

There is no current standard for dedicated outdoor air systems.

Beginning July 24, 2023, representations with respect to energy use or efficiency of direct expansion-dedicated outdoor air systems must be based on testing conducted in accordance with Appendix B to Supart F of Part 431. Manufacturers may elect to use this appendix early.