ANSI Approves ACCA Manual S® - 2023 (Residential Equipment Selection)

Alexandria, VA (September 11, 2023) - The American National Standards Institute (ANSI) recently issued approval of proposed revisions to ANSI/ACCA Manual S® - 2014, Residential Equipment Selection. The approved standard will be designated as the 2023 edition. The standard is maintained by the Air Conditioning Contractors of America (ACCA) under the auspices of the ANSI-accredited ACCA Standards Task Team (STT).

America is moving toward increased use of heat pumps to support the migration toward electrification. Additionally, there is an ever-increasing use of variable-capacity equipment. To address these changes, ACCA has updated accordingly. Along with setting clear requirements, the revised standard expanded its guidance for variable-capacity equipment.
“This new edition of Manual S is the culmination of several years of development with cooperation from contractors, users, OEMs, utilities, and other experts focused on equipment selection and sizing,” said Anthony Maynor, RightTek HVAC Training’s president and review committee chair. “We’re very grateful for the collective effort provided by the experts who contributed; the revised standard is something for which everyone can be proud.”
The Manual S standard provides procedures for selecting and sizing residential heating, cooling, dehumidification, and humidification equipment. The Normative Sections of the standard provide the equipment selection and equipment sizing criteria necessary to implement the standard's requirements.
It is anticipated that the Normative Sections will be made available online for free. A User’s Manual will also be available at a later date, containing informative guidance and examples based on the Normative Sections.
“We are pleased that the 2023 edition of Manual S was ANSI approved in time to be referenced by the International Code Council’s (ICC) 2024 edition of the International Residential Code (IRC),“ said Barton James ACCA president and CEO. “The National Institute of Standards and Technology (NIST) research shows the impact of over-sizing HVAC equipment and under-sizing the ductwork; it creates a huge energy penalty. The Environmental Protection Agency estimates that half the homes in county have poorly installed HVAC systems, some losing as much as 40% of their energy efficiency. I think we can all agree we need to be able to 'prove it' to our customers. To show that we can deliver predictable results because we’ve followed proven industry standards like ACCA’s Manual S.“
For more information about Manual S or ACCA, please contact Melissa Broadus, ACCA director of member communications & committee liaison, at or (703) 824-8842.