What is the Georgia State Energy Code, and does my remodel trigger it?

The Georgia State Minimum Standard Energy Code is the 2021 International Energy Conservation Code (IECC) with Georgia-specific amendments adopted by the Georgia Department of Community Affairs (DCA) under O.C.G.A. 8-2-20 (the Uniform Codes Act). Atlanta and most of the metro sit in IECC Climate Zone 3A (warm humid), which calibrates the prescriptive envelope, fenestration, and mechanical requirements differently than the colder northern Georgia mountains in Zone 4A. Code is updated on roughly a 6-year cycle and was last refreshed in 2020 with Georgia amendments published in 2023.

For a residential remodel, the code engages whenever you alter the building thermal envelope (insulation, windows, doors, air-sealing) or the mechanical, ventilation, or service-water-heating systems. Headline requirements in Zone 3A include ceiling insulation R-49 (R-30 in unconditioned attic spaces with limited area), wall insulation R-13 plus R-5 continuous or R-20 cavity, window U-factor 0.32 or lower with SHGC 0.25 or lower, mandatory whole-house mechanical ventilation per ASHRAE 62.2 (typically a balanced ERV or HRV or a continuously running bath exhaust at calculated CFM), duct leakage testing with a maximum of 4 CFM25 per 100 sq ft of conditioned floor area for ducts in unconditioned space, and HVAC equipment minimum efficiencies aligned with the federal DOE rule for the region.

The code distinguishes between a Repair (replacement of existing components in kind, exempt from upgrade), an Alteration (improvements that must meet code only for the altered scope), and a Substantial Renovation (where substantial portions of the envelope or systems are reworked, triggering a fuller upgrade obligation). Like-for-like window replacement using existing rough openings still must meet the U-factor and SHGC limits. New ducts in unconditioned attic space must meet R-8 insulation. Compliance is verified through the prescriptive path, the trade-off path using REScheck software, or the performance path using energy modeling. Atlanta Office of Buildings requires the REScheck or model output as part of the plan submission for any project that disturbs more than 50% of the envelope.