NJ Energy Subcode: ASHRAE 90.1-2019 Mandatory for Commercial — IECC-C Deleted

The statutory and regulatory framing

• N.J.A.C. 5:23-3.18 — NJ UCC energy subcode.
• Residential low-rise — 2021 IECC.
• Commercial and residential >3 stories — ASHRAE Standard 90.1-2019. IECC commercial provisions explicitly deleted.
• Effective — mandatory for permits submitted on or after March 6, 2023 (replacing prior 2018 IECC / ASHRAE 90.1-2016).
• Administering agency — NJ Department of Community Affairs (DCA).

Primary source: nj.gov/dca.

The IECC-C deletion — why it matters

In most states (MD, VA, PA, DE), commercial buildings have an option: comply with IECC Chapter 4 commercial provisions, or use ASHRAE 90.1 as an alternate compliance path. Designers choose based on project type and efficiency strategy. NJ removes that choice — ASHRAE 90.1-2019 is the only acceptable compliance path for commercial and residential >3 stories.

N.J.A.C. 5:23-3.18 redefines "IECC-Commercial Provisions" to mean "meeting the requirements of ASHRAE Standard 90.1." In effect, when the regulations reference IECC-C, they point to ASHRAE. This is a distinctive NJ structural choice.

ASHRAE 90.1-2019 compliance — what's in and out

Key implications for designers:

• Envelope — ASHRAE 90.1-2019 Chapter 5 requirements for opaque, fenestration, and air leakage.
• HVAC — ASHRAE 90.1-2019 Chapter 6 requirements including equipment efficiencies, controls, economizers, and commissioning.
• Service water heating — ASHRAE 90.1-2019 Chapter 7.
• Power — ASHRAE 90.1-2019 Chapter 8 is optional under NJ amendments.
• Lighting — ASHRAE 90.1-2019 Chapter 9 requirements for allowances, controls, and exterior lighting.
• Other equipment — ASHRAE 90.1-2019 Chapter 10.
• Energy cost budget method, performance rating method — available performance paths per ASHRAE 90.1.

Compliance software — use the 90.1 COMcheck

COMcheck-web from the US DOE supports NJ commercial compliance, but designers must use the ASHRAE 90.1 version of the program — not the IECC-C version. Submitting an IECC-C COMcheck report for an NJ commercial building will not demonstrate compliance under N.J.A.C. 5:23-3.18.

Residential low-rise — 2021 IECC

For residential buildings three stories or fewer, NJ uses the 2021 IECC with specific amendments:

• Increased insulation levels.
• Improved window and door performance (U-factor, SHGC).
• Enhanced air sealing.
• Mandatory duct leakage testing.
• Required mechanical ventilation systems.
• Optional blower door testing for airtightness.

Estimated 8.66% lower energy cost compared to 2018 IECC baseline for a comparable residential building.

The Energy Master Plan trajectory

NJ's Energy Master Plan (EMP) outlines a strategic push toward 100% clean energy by 2050 with interim goals including 100% clean electricity by 2035. The 2024 EMP, finalized in 2025, emphasizes:

• Maximum electrification of transportation and building sectors.
• Transition toward an increasingly clean electricity grid.
• Building-sector carbon reduction through performance standards.

Ongoing legislative efforts (e.g., the proposed "Zero Energy Construction Act") aim to require all new residential and commercial developments to be zero-energy ready — consistent with neighboring MD and DC programs (see our MD BEPS essay for MD's analogous direction).

Implications for commercial designers

• Use ASHRAE 90.1-2019 from schematic. Don't draft to IECC commercial and plan to cross-walk.
• Envelope performance requirements may differ meaningfully from a PA or DE project design at similar climate zone.
• HVAC commissioning per ASHRAE Chapter 6 is the path, not IECC-C alternatives.
• Lighting power allowances per ASHRAE Chapter 9.
• Documentation through ASHRAE-version COMcheck or detailed calculations.
• Commissioning requirements for larger systems under ASHRAE 90.1 must be planned into the construction timeline.

Cross-state contrast

• Pennsylvania. UCC adopts IECC with state amendments; local opt-out possible on enforcement. See our PA UCC essay. Commercial can typically use either IECC-C or ASHRAE 90.1.
• Maryland. MBPS adopts IECC with state-level energy stringency above baseline. Montgomery County requires ASHRAE 90.1-2022 + energy modeling — parallel to NJ's 2019 mandate but newer version. See our MD MBPS essay and MD BEPS essay.
• Virginia. USBC adopts energy code as part of IECC package; both IECC-C and ASHRAE 90.1 paths available. See our VA USBC essay.
• Delaware. Energy code adoption varies by jurisdiction; no statewide BEPS analog.
• New Jersey. IECC-C deleted; ASHRAE 90.1-2019 only for commercial. Distinctive structural choice.

What's next — anticipated shifts

NJ's energy subcode has historically updated on approximately 3-year cycles following ASHRAE and IECC release cadence. A move to ASHRAE 90.1-2022 (or later) for commercial is plausible in coming years, following MD Montgomery County's pattern. The EMP trajectory implies even more stringent performance standards will land as zero-energy-ready concepts move from policy into code.

What to do with this

If you're designing commercial in NJ: ASHRAE 90.1-2019 from day one. Use the 90.1 COMcheck. Budget for commissioning per Chapter 6.

If you're crossing from PA, VA, or DE: recalibrate. Don't carry IECC-C compliance templates into NJ.

If you're working residential >3 stories: ASHRAE 90.1 applies, not residential IECC.

If you're budgeting a large NJ commercial project: energy modeling and commissioning costs should be line items.

For adjacent essays, see Camden UCC, NJ MLUL, and MD Energy + BEPS.

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