The Nonresidential and Multifamily Alternative Calculation Method (ACM) Reference Manual explains the requirements for approval of nonresidential and multifamily Title 24 compliance software in California. Approved compliance software is used to demonstrate minimum compliance with the Building Energy Efficiency Standards (Energy Code), CALGreen, or any metric approved by the California Energy Commission (CEC). Definitions and terms in this manual may be found in the 2022 Energy Code. The procedures and processes described in this manual are designed to provide consistency and accuracy while preserving integrity of compliance. This manual addresses compliance software for nonresidential buildings, hotels, motels, and multifamily buildings as outlined in Title 24, Part 6, Subchapter 5, §140.1 and Subchapter 11, §170.1. A separate ACM reference manual applies to single-family residential buildings. The approval process for nonresidential compliance software programs is specified in Title 24, Part 1, Section 10-101 through Section 10-110 of the California Code of Regulations.