Louisiana REScheck Requirements (2026)

Key facts:

• 2021 IECC with LA Amendments — Current

• All 64 Parishes = Climate Zone 2A

• Blower Door: 7 ACH50 Mandatory (from 7/1/24)

• No Buried Ducts in Zone 2A

​

Louisiana commonly requires REScheck for: new residential construction, additions and alterations, reconstruction and extensive alterations, conditioned detached structures and ADUs. REScheck is explicitly named as the compliance documentation tool on the official Louisiana DNR energy codes page; the completed report is submitted to the Office of the State Fire Marshal.

​

Louisiana's residential energy code is the 2021 International Energy Conservation Code with Louisiana amendments, administered by the Louisiana State Uniform Construction Code Council (LSUCCC). The IRC was effective July 1, 2023; energy-specific amendments became effective March 2024. Louisiana made a critical statewide amendment: all 64 parishes are declared Climate Zone 2 (Hot-Humid) regardless of geographic location.

 

Statewide Code Structure

• 2021 IECC with Louisiana amendments — effective July 1, 2023 (IRC); energy amendments effective March 2024

• Administered by LSUCCC; enforced by parish building departments and the Office of the State Fire Marshal

• NGBS 2020 and ENERGY STAR certification deemed to exceed the state code

• Applies to all new construction, reconstruction, additions, and extensive alterations

• Appendix AQ (Tiny Houses) included with inspections required; Appendix J (Existing Buildings) is parish-optional

 

Common Permit Requirements

• REScheck compliance report — explicitly named on the Louisiana DNR energy codes page; submitted to the Office of the State Fire Marshal

• Manual J HVAC load calculations

• Window and door schedule (U-factor max 0.40, SHGC max 0.25)

• Insulation R-value specs and Louisiana Insulation Certificate (posted permanently in a utility area)

• Blower door test results — 7 ACH50 max; mandatory from July 1, 2024; certified tester required

• Duct leakage test results (4 CFM25/100 sq ft to outside; 8 CFM25/100 sq ft total)

• Energy Efficiency Certificate posted at electrical panel

 

Louisiana's Three Compliance Pathways

Pathway  ·  How It Works

• Prescriptive (§R402.1.3):  Ceiling R-38, walls R-13, floor R-13, crawlspace R-0, slab N/A, window U-0.40/SHGC 0.25. REScheck not required for straightforward projects. Blower door/duct testing still mandatory.

• UA Trade-Off / REScheck (§R402.1.5):  Total UA ≤ reference design UA. REScheck explicitly named as documentation tool. SHGC 0.25 mandatory, can't be traded off.

• Performance / ERI (§R405/R406):  Proposed energy cost ≤ standard reference design. Louisiana removed the R401.2.5 additional efficiency requirement — no extra package needed. HERS Rater required.

 

⚠ Louisiana Made a Critical Statewide Zone Amendment: While northern Louisiana parishes near the Arkansas and Mississippi borders technically fall in IECC Zone 3A geographically, Louisiana amended its 2021 IECC adoption to declare all 64 parishes as Zone 2 for energy code purposes. Every project — New Orleans to Shreveport to Monroe — uses the same Zone 2 table, unlike Mississippi or Arkansas, which may use Zone 3A values for some counties.

 

Louisiana Energy Code Requirements — Zone 2A Statewide

Assembly  ·  R-Value / U-Factor  ·  Notes

• Ceiling / Attic:  R-38 min / U-0.030   —   Louisiana amendment — base 2021 IECC Zone 2 requires only R-30; LA raised it to R-38

• Wood Frame Walls:  R-13 cavity / U-0.082   —   Statewide minimum; no continuous insulation required on the prescriptive path

• Floor (above unconditioned space):  R-13 min   —   Base 2021 IECC Zone 2 requirement

• Basement Walls:  Not Required   —   Not required in Warm-Humid locations — all of Louisiana qualifies

• Crawlspace Walls:  R-0 / U-0.477   —   No insulation required in Zone 2 warm-humid locations

• Slab Edge:  N/A   —   Not required in Zone 2

• Windows:  U-0.40 max / SHGC 0.25 max   —   SHGC 0.25 mandatory — cannot be traded off

• Skylights:  U-0.55 max   —   May be excluded from SHGC requirements if skylight SHGC ≤ 0.30

 

Blower Door and Air Sealing Requirements

⚠ Blower Door Testing Became Mandatory on July 1, 2024: Before that date, Louisiana allowed visual inspection as an alternative. Effective July 1, 2024, blower door testing by a certified tester is mandatory for all new residential construction. Written reports signed by the tester go to the Building Code Enforcement Official. Exception: buildings/units 1,500 sq ft or smaller — verify with the local jurisdiction.

• Maximum air leakage: 7.0 ACH50 or 0.28 CFM per sq ft of dwelling unit enclosure area (whichever is met)

• Testing per ANSI/RESNET/ICC 380, ASTM E779, or ASTM E1827

• More lenient than Tennessee (3 ACH50) but stricter than the prior visual-inspection-only path

• For multifamily with 8+ units: at least 7 units or 20% (whichever greater) must be tested

 

Mechanical Ventilation Trigger: if a blower door result is below 3 ACH50, whole-house mechanical ventilation is required per §M1507.3 — ERV or HRV systems are acceptable. Documentation must be available at final inspection.

 

Duct Requirements in Louisiana

• All supply/return ducts outside conditioned space: R-8 minimum (no R-6 exception for smaller ducts, except ducts under 3 inches diameter)

• Buried duct installations are PROHIBITED in Zone 2A — a Louisiana-specific deletion from the base 2021 IECC, which otherwise permits buried ducts in Zones 0A–3A

• Ductwork in floor cavities over unconditioned space: continuous air barrier required, R-10 minimum in the separating cavity

• Air handlers must have manufacturer's air leakage designation ≤ 2% of design airflow

 

Duct Leakage Testing

• Post-construction (leakage to outside): ≤ 4 CFM25 per 100 sq ft

• Post-construction (total leakage): ≤ 8 CFM25 per 100 sq ft

• Rough-in test: ≤ 6 CFM25 per 100 sq ft

• Required for all duct systems including those within conditioned space (tested to the total leakage standard)

• Framing cavities may NOT be used as ducts; all seams sealed with mastic, not tape alone

 

Why No Buried Ducts in Louisiana? Buried ducts in hot, humid climates create condensation risk where cold supply air meets warm, moist attic insulation. Louisiana's prohibition protects against this failure mode common in Gulf Coast construction. Builders familiar with buried duct techniques from Florida or Texas should verify this is not permitted in Louisiana.

 

Is REScheck Required in Louisiana?

• All new low-rise residential construction (3 stories or fewer)

• Single-family homes, duplexes, and townhomes

• Low-rise multifamily residential (3 stories or fewer)

• Reconstruction

• Additions to homes previously built under the IRC

• Extensive alterations

• Accessory dwelling units (ADUs)

• Conditioned barndominiums

 

High-rise multifamily (4+ stories) uses COMcheck, not REScheck, per the Louisiana DNR energy codes page — the commercial energy code governs buildings over 3 stories.

 

Louisiana-Specific Notes

• REScheck explicitly named on the official Louisiana DNR/DENR page: “Compliance with the IECC is documented by the forms generated by REScheck…”

• Completed REScheck report is submitted to the Office of the State Fire Marshal

• The Louisiana Insulation Certificate (separate from the standard energy certificate) must be permanently posted in a utility area

• NGBS 2020 and ENERGY STAR certification deemed to exceed code — no separate IECC documentation needed

• R401.2.5 Additional Efficiency Requirements removed from Louisiana's adoption — no extra package required (unlike New Jersey's R408)

• HVAC must be sized per ACCA Manual J or equivalent; all permanently installed lighting must be high-efficacy

 

Common REScheck Failure Reasons in Louisiana

Most Common Errors

• SHGC failure — 0.25 max is the most common Louisiana failure; west-facing glazing on coastal/lake/Gulf-front homes regularly fails

• Wrong ceiling R-value — entering R-30 (base 2021 IECC Zone 2) instead of Louisiana's amended R-38

• Using Zone 3A values — some northern Louisiana builders assume their parish is Zone 3A based on geography; all parishes are Zone 2 per Louisiana's amendment

• Missing Louisiana Insulation Certificate — a Louisiana-specific requirement separate from the standard energy certificate

• Specifying buried ducts — prohibited in Zone 2A; requires plan revision before permit issuance

 

Mechanical & Field Issues

• Blower door failures — top-plate bypasses, recessed lighting, electrical penetrations, HVAC boot-to-ceiling gaps are common failure points

• Duct leakage failures — flex duct connections, plenum connections, air handler connections in hot attic conditions

• Duct insulation below R-8 — builders from states allowing R-6 for ducts over 3 in. diameter sometimes under-spec Louisiana projects

• Missing mechanical ventilation documentation when blower door result is below 3 ACH50

• Missing duct testing documentation — mandatory since July 1, 2024

 

Major Cities and Jurisdictions

New Orleans & Jefferson Parish (Zone 2A)

Coastal Gulf environment with extreme heat, humidity, and hurricane wind load requirements. SHGC 0.25 compliance is critical. Post-hurricane reconstruction projects are subject to the current energy code.

 

Baton Rouge & East Baton Rouge Parish (Zone 2A)

State capital and second-largest metro. Requires REScheck submission, blower door results, and duct leakage documentation for new construction permits.

 

Shreveport & Caddo Parish (Zone 2A)

Despite being ~200 miles from the Gulf and geographically closer to Zone 3A, the statewide Zone 2 amendment applies here regardless.

 

Lafayette (Zone 2A)

Active market driven by oil and gas employment. The buried duct prohibition is particularly relevant here given historical use of attic-buried flex duct systems.

 

Lake Charles, Monroe & Alexandria (Zone 2A)

All Zone 2A per the statewide amendment, with significant post-hurricane reconstruction activity in Lake Charles.

 

Frequently Asked Questions

What energy code does Louisiana currently use?

The 2021 IECC with Louisiana-specific amendments, effective July 1, 2023 (IRC) with energy amendments effective March 2024. Key amendments: all 64 parishes declared Zone 2 statewide; ceiling insulation raised to R-38; blower door set at 7 ACH50; buried ducts prohibited in Zone 2A; R401.2.5 additional efficiency requirements removed.

 

Is REScheck required in Louisiana?

Yes. The Louisiana DNR states: “Compliance with the IECC is documented by the forms generated by REScheck for single family and low rise multi-family buildings of three stories or less.” The completed report is submitted to the Office of the State Fire Marshal.

 

What climate zone is Louisiana in?

All 64 parishes are Zone 2 (Hot-Humid) per Louisiana's amendment — even northern parishes that are geographically closer to Zone 3A.

 

Is blower door testing required in Louisiana?

Yes, mandatory since July 1, 2024. Max 7.0 ACH50 or 0.28 CFM/sq ft. Certified tester required; written signed report to the BCEO. Exception for buildings/units ≤ 1,500 sq ft — verify locally. Below 3 ACH50 triggers mandatory mechanical ventilation.

 

What is the ceiling insulation requirement?

R-38 statewide — Louisiana raised this from the base 2021 IECC Zone 2 value of R-30. R-30 satisfies where full-height uncompressed R-30 extends over the wall top plate at the eaves.

 

What is the SHGC requirement?

0.25 maximum for all glazed fenestration statewide — mandatory, can't be traded off. The most common REScheck failure in Louisiana.

 

Why are buried ducts prohibited?

Moisture management — cold supply air in ducts buried in warm, moist attic insulation creates condensation risk, mold growth, and duct failure. Louisiana deleted the base code's buried-duct allowance for Zone 2A specifically.

 

Are barndominiums required to comply?

Yes, conditioned barndominiums must comply with the 2021 IECC with Louisiana amendments. SHGC 0.25, the buried duct prohibition, and mandatory blower door testing all apply.