Maryland Energy Code Compliance Calculator

Evaluate building envelope and HVAC system compliance with the Maryland Energy Code (based on IECC 2021 / ASHRAE 90.1-2019, Climate Zone 4A). Enter your building's actual values to check compliance against Maryland's prescriptive requirements.

Building Envelope Inputs

HVAC System Inputs

Formulas & Compliance Logic

Prescriptive Compliance: Each building component is compared directly against Maryland's IECC 2021 Climate Zone 4A prescriptive table values:

  • Envelope Pass/Fail: Actual R-value ≥ Required R-value (insulation); Actual U-factor ≤ Required U-factor (windows); Actual ACH50 ≤ 3.0
  • HVAC Pass/Fail: Actual efficiency ≥ Federal/IECC minimum for system type
  • Weighted Performance Score:
    Score = Σ(weight_i × perfRatio_i)
    where perfRatio = actual/required (higher-is-better) or required/actual (lower-is-better), capped at 1.5
  • Energy Savings vs. Baseline:
    Savings% ≈ (Score − 1.0) × 100%
    Weights: Air Leakage 20%, HVAC 20%, Walls 18%, Windows 15%, Roof 12%, Floor 8%, Lighting 7%
  • Annual Cost Impact:
    Annual Savings ≈ $2,200 × (Score − 1.0) × 0.5
    Based on Maryland average residential energy cost (EIA 2023)

Assumptions & References

  • Maryland is entirely in IECC Climate Zone 4A (Mixed-Humid)
  • Prescriptive requirements from IECC 2021 Table R402.1.2 (residential)
  • Commercial buildings: ASHRAE 90.1-2019 (adopted by Maryland)
  • HVAC minimums: DOE 2023 federal efficiency standards + IECC 2021 §R403.6
  • Air leakage: 3.0 ACH50 maximum per IECC 2021 §R402.4.1.2
  • Lighting: 0.90 W/ft² whole-building average per ASHRAE 90.1-2019 Table 9.6.1
  • Water heater UEF: DOE 2015 standards; exact minimum varies by fuel type and capacity
  • Annual energy cost baseline: $2,200/yr (EIA 2023 Maryland residential average)
  • Wall R-value: R-20 cavity OR R-13 cavity + R-5 continuous insulation (ci) both acceptable
  • This tool evaluates the prescriptive compliance path only; performance path (energy modeling) may allow trade-offs between components
  • Always verify requirements with your local Authority Having Jurisdiction (AHJ) and use REScheck/COMcheck for official permit documentation
  • Maryland Energy Administration: energy.maryland.gov

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