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NYC REScheck & NYCECC Requirements (2026)

Key facts:

  • 2025 NYCECC — Mandatory March 30, 2026

  • Enacted by Local Law 47 of 2026

  • Climate Zone 4A — All Five Boroughs

  • REScheck Accepted (NY State Version Required)

 

New York City requires residential energy-code compliance under the 2025 New York City Energy Conservation Code (NYCECC), enforced by the NYC Department of Buildings (DOB) — a separate code from the rest of New York State, though based on the same 2024 IECC foundation. REScheck is accepted for NYC residential compliance, but only the New York State version matching the code edition currently in effect. NYC projects also face mandatory third-party blower door testing, thermal-bridge documentation, and stricter enforcement than most statewide jurisdictions.

NYC operates under its own energy code, legally separate from the statewide ECCCNYS that covers the rest of New York (see our New York State REScheck guide for the statewide code, NYStretch, and the rest of the state's climate zones). The current edition is the 2025 NYCECC, enacted by Local Law 47 of 2026 (based on Int. No. 1490-B), and administered by the NYC Department of Buildings rather than the state Department of State. It became mandatory March 30, 2026.

 

Current NYC Energy Code (2025 NYCECC)

Local Law 47 of 2026 conforms the New York City Energy Conservation Code to the 2025 statewide code while retaining NYC-specific amendments. The 2025 NYCECC incorporates the 2024 IECC model code provisions along with the latest NYSERDA NYStretch Code — meaning NYC's baseline already includes stretch-code-level efficiency measures that most of the rest of the state only gets if a municipality separately opts in.

  • 2025 NYCECC — enacted by Local Law 47 of 2026, based on Int. No. 1490-B

  • Incorporates the 2024 IECC plus the latest NYSERDA NYStretch Code provisions

  • Administered and enforced by the NYC Department of Buildings (DOB), not the state DOS

  • Mandatory compliance date: March 30, 2026

  • Grace period: a complete, diligently-pursued energy submission filed before March 30, 2026 may remain under the 2020 NYCECC, provided there's no material compliance change afterward

  • Applies to new residential construction, additions, and alterations citywide

 

Is REScheck Accepted for NYC Compliance?

Yes. Under 1 RCNY §5000-01, REScheck (the U.S. Department of Energy's software) is explicitly approved for residential buildings in New York City — new construction, additions, and alterations using whole-building analysis. A tabular analysis format (manual comparison) is also accepted as an alternative. Commercial buildings use COMcheck instead.

 

Use the Current Edition, New York State Version: DOB's rule requires that only the "New York State version" of REScheck be used, and that it reflect the energy code edition in effect when the application is filed. A generic or out-of-state REScheck build, or a report run under an old code year, is a common cause of rejected submissions — confirm the current accepted version with DOB before filing.

 

Common DOB Filing & Permit Requirements

  • Energy analysis on construction drawings, signed and sealed by a registered design professional

  • REScheck compliance report (or tabular analysis), reflecting the current NYCECC edition

  • Supporting Documentation Index — every proposed value (insulation, fenestration, mechanical) must be listed and traceable

  • Third-party blower door / air leakage test report

  • Thermal-bridge documentation per Section R402.7

  • Mechanical ventilation and equipment schedules

  • Commissioning documentation for residential projects over 10,000 sq ft or 960,000 Btu/h combined mechanical capacity

 

NYC Climate Zone & Prescriptive Requirements

All five boroughs fall within IECC Climate Zone 4A. The prescriptive residential table below reflects the 2025 NYCECC (Table R402.1.3 and R402.1.2).

Assembly  ·  Requirement  ·  Notes

  • Ceiling:  R-49   —   Applies citywide

  • Wood Frame Walls:  R-30 cavity, or R-20+5ci, or R-13+10ci, or R-20 continuous   —   Cavity-only below R-30 not permitted

  • Floor:  R-30 cavity, or R-19+7.5ci, or R-20 continuous   —   Applies above unconditioned space

  • Below-Grade / Crawlspace Walls:  R-15 continuous, or R-19 cavity, or R-13+5ci   —   Same requirement for both assembly types

  • Unheated Slab:  R-10 continuous, 4 ft depth   —   Standard slab-edge treatment

  • Heated Slab:  R-10 continuous at 4 ft perimeter PLUS R-10 under the full slab   —   Stricter than an unheated slab — full-slab insulation required

  • Windows:  U-0.27 max / SHGC 0.40 max   —   SHGC maximum applies citywide

  • Skylights:  U-0.50 max   —   Applies citywide

 

Air Leakage, Thermal Bridging & Mechanical Requirements

Air Leakage / Blower Door Testing

  • Maximum 3.0 air changes per hour at 0.2 inch water gauge (Section R402.5.1.3)

  • Testing mandatory for all new residential buildings — no visual-inspection alternative

  • Must be performed by an approved third-party tester following ASTM standards

  • Building thermal envelope is also verified in the field during construction, separate from the final blower door result

 

Thermal Bridging (Section R402.7)

Construction documents must identify thermal bridges — points where conductive materials (structural connections, cladding supports, fenestration connections) allow heat to bypass the insulated envelope — and document linear thermal bridge types, aggregate lengths, and Ψ-values from Table R402.7, or provide an approved alternate calculation. Continuous insulation is required for certain assemblies to meet the prescriptive or component-performance paths.

 

Ventilation & Electrification

  • Mandatory heat-recovery or energy-recovery ventilation (ERV/HRV) in dwelling units

  • Electric-resistance heating capped at 25% of the design heating load

  • Electric-resistance heating permitted only when outdoor design temperature is below 17°F

  • Ventilation coordination required alongside airtightness — tighter envelopes under the 3.0 ACH50 limit increase reliance on mechanical ventilation for indoor air quality

 

Enforcement Under Local Law 47

Local Law 47 of 2026 gives DOB multiple checkpoints to verify compliance rather than relying on the filed paperwork alone.

  • Progress inspections during construction

  • Final inspection required before Certificate of Occupancy is issued

  • Third-party air leakage (blower door) testing following ASTM standards

  • Building thermal envelope verification in the field during construction

  • Detailed plan examination review, with correction notices common for incomplete or inconsistent energy documentation

 

Common REScheck & NYCECC Failure Reasons in NYC

Most Common Errors

  • Using a REScheck version or code-year edition that doesn't match the current 2025 NYCECC filing requirement

  • Missing or incomplete thermal-bridge documentation under Section R402.7

  • Window U-factor or SHGC entered above the 0.27 / 0.40 maximums

  • Missing continuous insulation where the prescriptive path requires it (cavity-only options below R-30 walls are not permitted)

  • Confusing heated-slab and unheated-slab insulation requirements — heated slabs need full-slab R-10, not just the 4 ft perimeter

 

Mechanical & Envelope Issues

  • Blower door failures at the strict 3.0 ACH50 threshold — rim joists, party-wall penetrations, and window rough openings are common failure points in NYC's older and infill building stock

  • Missing or undocumented ERV/HRV systems in dwelling units

  • Electric-resistance heating specified above the 25% design-load cap, or outside the below-17°F condition

  • Missing commissioning documentation on qualifying larger residential projects (over 10,000 sq ft or 960,000 Btu/h combined capacity)

 

Major NYC Boroughs

Manhattan

Dense infill and high-value renovation work means DOB plan examination here tends to scrutinize envelope performance, thermal-bridge documentation, and ventilation coordination especially closely.

 

Brooklyn

One of NYC's most active residential permit markets, with a large share of additions, gut renovations, and new low-rise construction subject to the full 2025 NYCECC.

 

Queens

A mix of single-family, multifamily, and larger residential projects — larger developments here are more likely to trigger the commissioning requirement.

 

The Bronx

Active new-construction and conversion market; ventilation-system compliance and blower door testing are routine parts of permit review.

 

Staten Island

NYC's most suburban borough by building stock, with a higher share of detached single-family construction — still fully subject to the citywide 2025 NYCECC rather than the statewide ECCCNYS.

 

Frequently Asked Questions About NYC REScheck & NYCECC

Does NYC use the same energy code as the rest of New York State?

No. New York City is excluded from the statewide ECCCNYS and operates its own New York City Energy Conservation Code (NYCECC), administered by the NYC Department of Buildings rather than the state Department of State. Both are based on the 2024 IECC, but they're separate codes with separate enforcement.

 

What is Local Law 47 of 2026?

Local Law 47 of 2026 (based on Int. No. 1490-B) is the law that conforms the NYC Energy Conservation Code to the 2025 statewide energy code while keeping NYC-specific amendments — inspections, thermal-bridge documentation, and enforcement provisions. It's the legal basis for the current 2025 NYCECC.

 

When does the 2025 NYCECC become mandatory?

March 30, 2026. A complete, diligently-pursued energy submission filed before that date may remain under the 2020 NYCECC, as long as there's no material compliance change to the project afterward.

 

Is REScheck accepted for NYC residential compliance?

Yes, under 1 RCNY §5000-01, for new residential buildings, additions, and alterations using whole-building analysis. It must be the New York State version of REScheck, reflecting the NYCECC edition in effect when the application is filed — an outdated or generic version is a common cause of rejected filings.

 

What is NYC's blower door / air leakage requirement?

Maximum 3.0 ACH50 at 0.2 inch water gauge, tested by an approved third party following ASTM standards. Testing is mandatory for all new residential buildings — there's no visual-inspection alternative.

 

What is thermal bridging, and what does NYCECC require?

Thermal bridging is heat transfer through conductive building elements — structural connections, cladding supports, fenestration connections — that bypass the insulated envelope. Section R402.7 requires construction documents to identify these bridges and document their type, aggregate length, and Ψ-value, or provide an approved alternate calculation, with continuous insulation required for certain assemblies.

 

Does NYC require mechanical ventilation in dwelling units?

Yes. Heat-recovery or energy-recovery ventilation (ERV/HRV) is mandatory in dwelling units under the 2025 NYCECC, largely because the tighter 3.0 ACH50 envelope requirement increases reliance on mechanical ventilation for indoor air quality.

 

What are NYC's rules on electric-resistance heating?

Electric-resistance heating is capped at 25% of a building's design heating load, and is only permitted when the outdoor design temperature is below 17°F.

 

Does the NYCECC include NYStretch?

Effectively, yes. The 2025 NYCECC was developed incorporating the latest NYSERDA NYStretch Code provisions directly into its baseline — so NYC's standard requirement is already close to what a NYStretch-adopting municipality elsewhere in the state would require, without needing a separate local opt-in law.

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