Section C406.1/Additional Efficiency Package Options
IECC C406 requires commercial buildings to achieve additional efficiency beyond prescriptive requirements from a menu of options.
In addition to meeting the prescriptive requirements of Sections C402 through C405, buildings must achieve additional efficiency by selecting from a menu of options in Table C406.1. The number of required options depends on the building type and climate zone. Options include: more efficient HVAC equipment, reduced lighting power density, enhanced digital lighting controls, on-site renewable energy, dedicated outdoor air system, enhanced envelope performance, reduced air infiltration, and high-efficiency service water heating.
Why this section exists
The prescriptive requirements of the IECC set minimum baselines for envelope, HVAC, and lighting. Section C406 pushes buildings beyond those baselines by requiring additional measures from a menu of options. This "reach code" approach allows designers flexibility in choosing which systems to improve while ensuring every building achieves a specified level of performance above the prescriptive minimums. It also introduces requirements for emerging technologies like on-site renewables and dedicated outdoor air systems.
What plan reviewers look for
Plan reviewers check the energy code compliance form for which C406 options the project is using. They verify that the selected options are documented on the drawings and meet the specific requirements of the chosen option. For example, if "more efficient HVAC" is selected, the equipment schedule must show efficiencies exceeding the C403 baseline by the required margin.
Common violations
Related IECC requirements
Section C402 covers prescriptive envelope requirements. Section C403 covers prescriptive mechanical requirements. Section C405 covers prescriptive lighting requirements. Section C407 covers the total building performance method as an alternative to prescriptive compliance. ASHRAE 90.1 has equivalent additional efficiency requirements in its 2022 edition.