ICC E2 cheat sheet

The code official has authority to reject construction documents that do not demonstrate compliance with the energy code before issuing a permit.

Compliance paths include the prescriptive approach (component-based), the trade-off approach (allowable envelope or lighting trade-offs), and the performance approach (whole-building energy simulation).

Alternative materials or methods may be approved if the code official finds them equivalent in performance, safety, and quality to the code requirements.

The code applies to new construction, additions, alterations, and change of occupancy; historic buildings may be exempt if compliance would threaten historic character.

Construction documents must show insulation R-values, U-factors, fenestration U-factors and SHGC, lighting power densities, and mechanical equipment efficiencies.

The code official may require commissioning of mechanical and lighting controls to verify performance, with reports submitted to the building department.

Appeals of code official decisions go to the board of appeals, which may grant variances only when strict compliance causes practical difficulty and the intent of the code is met.

Penalties for noncompliance can include stop-work orders, fines, denial of certificate of occupancy, and legal action.

The code is updated on a 3-year cycle; local jurisdictions may adopt amendments, so always verify the effective edition for the project location.

Envelope compliance is demonstrated by meeting either prescriptive U-factor and SHGC limits or the total UA trade-off method.

Opaque envelope U-factors: roof U-0.048, wall U-0.064, floor U-0.064 for Climate Zone 5 (typical commercial values; verify edition).

Vertical fenestration U-factor max 0.55 and SHGC max 0.40 in Climate Zone 4; U-0.50 and SHGC 0.40 in Climate Zone 5.

Continuous air barrier required: seal joints, penetrations, and intersections; verify with visual inspection and, if required, blower door test.

Insulation installation must be verified for full coverage, no gaps or compression, and proper alignment with the air barrier.

Fenestration must be labeled with U-factor and SHGC certified by the National Fenestration Rating Council (NFRC).

Thermal bridging must be accounted for in U-factor calculations; use ASHRAE 90.1 Appendix A or manufacturer data.

Skylight U-factor max 0.65 and SHGC max 0.40 in Climate Zone 5; skylights must have curb insulation and sealed edges.

Mechanical equipment must meet minimum efficiency requirements in ASHRAE 90.1 Table 6.8.1-1 (e.g., packaged AC ≥ 13 SEER, gas furnace ≥ 80% AFUE).

Piping insulation required for heating and cooling piping, with minimum thickness based on pipe size and fluid temperature per Table 6.8.3.

Duct insulation minimum R-8 for supply ducts in unconditioned spaces, R-6 for return ducts; seal all duct joints with mastic or approved tape.

Service water heating: gas-fired storage water heaters ≥ 0.64 EF for 55-gallon units; electric ≥ 0.93 EF; recirculation systems require automatic controls.

Lighting power density (LPD) limits by space type: office 0.90 W/ft², retail 1.40 W/ft², warehouse 0.60 W/ft² (ASHRAE 90.1-2019 values).

Lighting controls required: occupant sensors in classrooms and conference rooms, time-switch controls for outdoor lighting, and daylight-responsive controls in daylit zones.

Mechanical ventilation must comply with ASHRAE 62.1; economizers required above 54,000 Btu/h cooling capacity in Climate Zones 4-5.

Energy recovery ventilation required for systems with minimum outdoor air ≥ 70% of supply air and capacity ≥ 5,000 cfm in some climates.

Plan review must verify compliance forms (e.g., COMcheck reports) are complete and consistent with drawings.

Field inspection verifies insulation R-values, air barrier continuity, fenestration labels, and equipment nameplate efficiencies match approved plans.

Duct leakage testing required for systems with capacity > 5,000 cfm; leakage must not exceed 4% of design airflow.

Building envelope air leakage test: verify air barrier installation and conduct blower door test if required by code; target ≤ 0.40 cfm/ft² at 75 Pa.

Lighting controls functional testing: verify occupant sensors, time switches, and daylight controls operate as designed and are calibrated.

Mechanical system commissioning: verify economizer operation, fan control, and sensor calibration; document results in commissioning report.

Final inspection checks that all required certificates (e.g., NFRC labels, equipment efficiency reports) are posted or submitted.

Noncompliance items must be corrected and re-inspected before certificate of occupancy is issued.