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IECC C403 — HVAC Systems (Commercial)

Updated Mar 25, 2026
Commercial HVAC efficiency: equipment minimums, economizers, energy recovery, controls, duct insulation.

IECC 2024: C403.3 equipment per ASHRAE 90.1. Unitary AC >=14 SEER2. Heat pumps >=15 SEER2. Furnaces >=80% AFUE. Economizers required >=54,000 Btu/h CZ2-8. Energy recovery when OA>70% or >5,000 CFM. Duct insulation R-6 supply, R-4 return. Commissioning required >25,000 sf.

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IECCHVACefficiencyeconomizercommissioning
DETAILS
code year
2024
code section
C403
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