North Carolina HVAC permit requirements

North Carolina writes one State Building Code for the whole state, and local code enforcement departments apply it. The Office of State Fire Marshal (OSFM) says it holds the administration side: ‘The responsibility for the administration of the North Carolina State Building Code granted to the North Carolina Office of State Fire Marshal by North Carolina General Statutes 143-139 and 58-78A-1.’ The permit counter is local. Charlotte’s is Mecklenburg County Code Enforcement, covered on its own page.

The 2018 North Carolina State Building Code. The 2024 edition is adopted but not yet mandatory. OSFM’s codes page says: ‘The following 2018 Codes were effective from January 1, 2019 and are currently effective.’

The 2024 date has moved more than once. In December 2024 OSFM wrote that the legislature ‘delays the effective date of the 2024 North Carolina State Building Code to 7/1/25.’ A later session law moved it again. OSFM’s March 2025 letter: ‘Section 5.12(b) of S.L. 2025-2 provides that the 2024 Code will become effective 12 months after the State Fire Marshal certifies that the following events have occurred:’ publication and distribution of the code, and the Residential Code Council being fully constituted. The legislature’s staff analysis (August 14, 2025) agrees.

OSFM’s March 2026 newsletter: ‘It is still a moving date, and we will update this as it changes, but as of this writing this letter is still current.’ We found no certification letter, so no effective date for the 2024 code is verified. Until then: ‘the 2018 North Carolina State Building Code remains in full force and should continue to be enforced as the governing standard, unless a building owner or his agent requests that the 2024 Code be applied to the project’.

OSFM’s December 2024 statement gives July 1, 2025 and keeps the energy code at 2018 pending legislative review. Both are superseded: the March 2025 letter says the energy code ‘became a permanent rule on March 24, 2025, after being subjected to legislative review pursuant to G.S. § 150B-21.3’, and the session law removed the July 2025 date. A 7/1/25 date on a contractor site is the stale one.

The 2018 administrative code lets an owner opt in before the date. Section 102.5, as OSFM quotes it: ‘Any rules that are adopted by the Building Code Council and approved by the Rules Review Commission shall be accepted by the Code Enforcement Official as an alternate method of construction prior to the effective date if requested by the owner or his agent.’ OSFM’s December statement adds that the 2024 code ‘shall be used for the entirety of the scope of work included in the project.’

For residential HVAC the 2024 edition mostly re-adopts 2018 text. OSFM’s statement: ‘Chapters 11 through 24 of the 2018 NCRC are included within the 2024 NCRC as per North Carolina General Assembly Session Law 2023-108 (H488), Sections 7 and 8 which became law on 8/16/23’. The Council’s proposal for the mechanical chapters: ‘The 2021 IRC Chapters 12 through 23 are deleted and substituted with the 2018 NCRC Chapters 12 through 23.’

Required to be performed. Submission cannot be demanded at permit. The residential code sizing section reads, in the Council’s proposal text: ‘Heating and cooling equipment and appliances shall be sized in accordance with ACCA Manual S or other approved sizing methodologies based on building loads calculated in accordance with ACCA Manual J or other approved heating and cooling calculation methodologies.’

North Carolina then adds a sentence that is unusual in the model-code world: ‘For permitting, inspections, certificate of compliance or certificate of occupancy, verification of Calculations for HVAC Systems—ACCA Manual D, ACCA Manual J, ACCA Manual S calculation submittals and review shall not be required.’ In 2019 OSFM answered whether that means no calculation is needed: ‘However, the load calculation is still a code requirement.’

Why the badge says “Varies”: the calculation is mandated, but a permit office is barred from requiring its submission, so there is no submitted-load-calc rule to mark “Required”.

OSFM’s interpretation names the enforcer: ‘the intended entity that would enforce the proper adherence to it would be the State Board of Examiners of Plumbing, Heating, and Fire Sprinkler Contractors’. It reproduces the board’s rule 21 NCAC 50 .0505, which includes: ‘When either a furnace, condenser, package unit or air handler in an existing residential heating or air conditioning system is replaced, the licensed HVAC contractor or licensed technician is required to perform a minimum of a whole house block load calculation.’ We did not retrieve the board’s current text.

The duct section names Manual D as one route: ‘Duct systems serving heating, cooling and ventilation equipment shall be installed in accordance with the provisions of this section and ACCA Manual D, the appliance manufacturer’s installation instructions or other approved methods.’ The Manual D submittal is covered by the same bar quoted above: a permit office cannot require it.

In 2023 a petitioner asked the Building Code Council to add, for the mechanical and residential codes: ‘load and sizing calculation submittals shall be required.’ The Council’s approved minutes record the outcome for the residential section: ‘This item was removed from the agenda as the Building Code Council no longer has the statutory authority per North Carolina General Assembly Session Law 2023-108 to amend the impacted portion of the NC Residential Code.’ The 2024 Mechanical Code review aid still carries the “shall not be required” sentence, with edit marks we could not resolve from the extracted text, so we have not verified the final wording of NCMC 312.1.

Not verified as a single value. The Council’s energy chapter proposal lists zones county by county, and the counties we saw are in 3A and 4A, so there is no one statewide zone. See the Charlotte-Mecklenburg page for that county.

We have researched one local office so far: Charlotte-Mecklenburg. The rest are not yet verified here.