Nebraska Energy Code Compliance Calculator — Insulation & HVAC Minimums by Climate Zone

Verify that your building's insulation R-values and HVAC equipment efficiencies meet Nebraska's adopted energy code (IECC 2021) requirements for Climate Zones 5A and 6A.

Your Proposed Insulation R-Values
Your Proposed HVAC Equipment

Compliance Logic & Formulas

Each component is checked against IECC 2021 minimum R-values and HVAC efficiency ratings:

  • Insulation Pass: Proposed R-Value ≥ Minimum R-Value (per IECC 2021 Table R402.1.2 for residential; Table C402.1.3 for commercial)
  • HVAC Pass: Proposed Efficiency ≥ Federal/IECC Minimum (AFUE %, SEER2, HSPF2)
  • Overall Compliance: ALL individual checks must pass
  • Gap Calculation: Δ = Proposed Value − Minimum Required Value (negative = non-compliant)

Nebraska Climate Zones (IECC 2021 Figure R301.1):

  • Zone 5A: Eastern & Central Nebraska — Lincoln, Omaha, Grand Island, Norfolk, Hastings, Kearney
  • Zone 6A: Western Nebraska / Panhandle — North Platte, Alliance, Scottsbluff, Valentine, Chadron

Assumptions & References

  • Based on IECC 2021 (International Energy Conservation Code), adopted as Nebraska's statewide energy code baseline.
  • Residential insulation minimums from IECC 2021 Table R402.1.2 (Insulation and Fenestration Requirements by Component).
  • Commercial insulation minimums from IECC 2021 Table C402.1.3 (Opaque Thermal Envelope Insulation Component Minimum Requirements).
  • Wall R-values represent combined cavity + continuous insulation (e.g., R-13 cavity + R-5 ci = R-18 combined; minimum shown as R-20 for Zone 5A/6A residential).
  • HVAC efficiency minimums reflect U.S. DOE 2023 federal standards for the Northern region (applicable to Nebraska): SEER2 ≥ 13.4 (AC), SEER2 ≥ 14.3 (HP), HSPF2 ≥ 7.5 (HP), AFUE ≥ 80% (furnace), AFUE ≥ 82% (boiler).
  • Mini-split minimums per DOE 2023: SEER2 ≥ 15.2, HSPF2 ≥ 8.1.
  • IECC 2021 recommends condensing furnaces (AFUE ≥ 92%) for Climate Zones 5 and 6.
  • This calculator uses a simplified prescriptive compliance path. Trade-off (UA alternative) and performance paths (energy modeling) may allow different combinations.
  • Local jurisdictions (Omaha, Lincoln) may have adopted amendments — verify with your local building department.
  • Does not include fenestration (window/door U-factor/SHGC) or air leakage (ACH50) checks.
  • Always consult a licensed engineer or energy code official for permit-level compliance determination.

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