ASHRAE 90.1 is not a code, but rather a standard that is referenced and adopted by the International Energy Conservation Code (IECC), a subset of the International Building Code (IBC). ASHRAE 90.1 provides guidelines for construction-related items such as wall and glazing insulation values, lighting power densities, and mechanical equipment efficiencies, with updates and revisions to this standard issued on a three-year basis. ASHRAE Standard 90.1 is the published energy standard for commercial buildings, with the exception of low-rise residential buildings. ASHRAE publishes various standards and guidelines for use and reference regarding HVAC systems.
