ACCA Announces Second ANSI Public Review for Additional Modifications to Proposed Manual D (Residential Duct Systems)

The Air Conditioning Contractors of America Educational Institute (ACCA-EI) Standards Task Team (STT) has announced an American National Standards Institute (ANSI) second public review period for proposed revisions to ANSI/ACCA Manual D - 2014, Residential Duct Systems. This second public review only addresses additional modifications based on comments received during the first ANSI public review period on Feb. 23, 2024.

As a widely used standard for residential duct design, Manual D uses heating and cooling loads to determine space air delivery requirements for residential applications. The proposed updates refine key definitions, provide clearer installation guidance, and address return air pathways to improve system efficiency and comfort.

ACCA’s technical work on manuals is one of the many ways we lead the industry, setting the standard for best practices that help HVACR professionals design systems that maximize efficiency for consumers.

“The revisions to Manual D reflect ACCA’s ongoing commitment to ensuring that HVACR professionals have the most accurate and practical guidance for residential duct system design,” said Wes Davis, ACCA director of technical services. “This second public review allows industry stakeholders to weigh in on some proposed revisions which add clarity to a standard that is critical to high-performance HVACR installations.”

The 30-day public review period runs from February 14 through March 16, 2025. HVACR professionals and industry stakeholders are encouraged to review the proposed changes and submit feedback.

Access the redline draft of proposed modifications and submit comments here.