The Air Conditioning Contractors of America Educational Institute (ACCA-EI) Standards Task Team (STT) announces an American National Standards Institute (ANSI) public review period for proposed “Addendum C” to ANSI/ACCA 3 Manual S – 2023, Residential Equipment Selection, as a revised industry standard. 

The 45-day ANSI public review period will be from June 6, 2025, to July 21, 2025. Proposed Addendum C will supplement ANSI/ACCA 3 Manual S – 2023, and Addenda A and B – 2024. 

The proposed addendum is to further clarify the existing requirements, correct some errors, and address user experience. Manual S provides procedures for selecting and sizing residential cooling equipment, heat pumps, electric heating coils, furnaces, boilers, ancillary dehumidification equipment, humidification equipment, and direct evaporative cooling equipment. 

A redline review draft of the proposed addendum can be obtained by going to the link shown below. Comments can be submitted by filling out and submitting the form at the same link:

ACCA ANSI Public Response Form - Proposed Addendum C to Manual S.

For more information about Manual S or ACCA, please contact Samantha Boyd, ACCA director of communications, marketing, and member engagement, at [email protected] or 703-824-8842.