Codes and Standards
Model Codes
  • International Mechanical Code (IMC): Mode code developed by the International Code Council (ICC) as part of the International Building Code (IBC). The IMC establishes minimum regulations for mechanical systems using prescriptive and performance-related provisions.
  • Uniform Mechanical Code (UMC): Model code developed by the International Association of Plumbing and Mechanical Officials (IAPMO) to govern the installation, inspection and maintenance of HVAC (heating, ventilating and air-conditioning) and refrigeration systems.


ASHRAE Standard 90.1 provides the minimum requirements for energy-efficient design of most buildings, except low-rise residential buildings. It offers, in detail, the minimum energy-efficient requirements for design and construction of new buildings and their systems, new portions of buildings and their systems, and new systems and equipment in existing buildings, as well as criteria for determining compliance with these requirements. AHRI participates on the ASHRAE 90.1 standards committee and the mechanical subcommittee.

  • 2019 edition: The current edition of 90.1 was published in October 2019, and is available, here.

California Building Energy Efficiency Standards – Title 24

California’s energy code is designed to reduce energy consumption in newly constructed and existing buildings. The standard applies to new construction of, and additions and alterations to, residential and nonresidential building. The California Energy Commission CEC) updates the Building Energy Efficiency Standards (Title 24, Parts 6 and 11) every three years by working with stakeholders in a public and transparent process.