A2L equipment is on the shelf while many adopted codes still say no
A2L equipment is what you can buy, and in a lot of jurisdictions the adopted mechanical code still predates the provisions that allow it.
That is the code gap creating trouble for residential changeouts. The 2024 editions of the International Residential Code, International Mechanical Code, International Building Code, and International Fire Code added provisions that allow A2L refrigerants for residential and light commercial comfort conditioning. The 2024 IRC expressly allows A2L refrigerants in residential applications.
Before the 2024 I-Codes, the model codes did not permit A2L refrigerants for that purpose. But an edition published by the International Code Council does not become law when ICC publishes it. A state or local jurisdiction has to adopt it by statute, rule, or ordinance.
That means the 2024 code book in your truck does not answer the permit question by itself. The edition governing the job is the edition your jurisdiction adopted.
The building department, not the code book, gives you the controlling answer
The edition year printed on a code book identifies the code cycle. It does not tell you when anyone started enforcing that edition.
Some states adopt statewide. Other states leave adoption to cities and counties. Two towns twenty minutes apart can be on different editions, and local amendments can change the result again.
The authoritative answer comes from your jurisdiction’s adopting ordinance or rule and from the authority having jurisdiction. ICC’s code adoption map is a useful starting point. It is not a substitute for asking the building department.
Adopting ordinances usually carry local amendments and a transition provision, and that provision governs work permitted or started before the effective date. Transition provisions vary by jurisdiction. Read the one that applies to you rather than assuming a permit date, an equipment order, or a signed proposal settles it.
Electrical work runs on the same logic. The three feet of working space in front of the disconnect is a requirement that arrived with a specific NEC edition, and so did the current rules on GFCI protection for outdoor HVAC equipment. Code edition is not background information. It decides what the inspector applies.
The 2024 I-Codes allow A2L, but adoption is still uneven
ACHR News reported on August 22, 2025 that the 2024 IBC, IMC, IFC, and IRC allow A2L refrigerants, but those codes “have not yet been widely adopted across the United States.” Cities and states are addressing the issue differently.
That difference reaches the jobsite. Contractors are seeing different warning label requirements, different leak detection system specifications, and different refrigerant charge limits across jurisdictions. A system accepted in one place can raise a permit or inspection question somewhere else. The local mechanical code answers the installation question, while what actually changed at shop level when A2L landed on the truck covers tooling, cylinders, recovery equipment, and which standard answers which question. When the dispute is specifically about sensors and shutoff, leak detection and lockout is the part of the work that varies most from one jurisdiction to the next.
ICC published amendment packages for jurisdictions still using older editions. The package titles are “Required Changes to the 2021 IRC,” “Required Changes to the 2018 IRC,” “Required Changes to the 2015 IRC,” and “Required Changes to the 2012 IRC.” Each is dated 06.14.24. ICC also published a consolidated document covering A2L changes across the IBC, IRC, IFC, and IMC, dated 06.14.2024.
ICC developed that material with AHRI, PHCC, ACCA, and HARDI. A jurisdiction on an older edition can use these amendments to allow A2L equipment without waiting for a full code cycle. That is worth knowing before you assume a red tag is final.
Texas shows how quickly an adopted code can change
On August 31, 2026, the Texas Commission of Licensing and Regulation adopted amendments to 16 TAC Chapter 75, the rules for the state’s Air Conditioning and Refrigeration Contractors program. The amendments affected sections 75.10, 75.80, 75.110, 75.121, and 75.124, and repealed section 75.28.
Those amendments updated the codes adopted by reference from the 2021 editions to the 2024 editions of the International Residential Code, International Mechanical Code, International Fuel Gas Code, and Uniform Mechanical Code. The effective date was September 1, 2026.
Treat that as an example of how fast the applicable code can move and how little notice a contractor gets, not as an answer for a different jurisdiction. Your own building department and adopting rule control your jobs.
The 2027 cycle has approved A2L amendments of its own, addressing installation in multifamily construction. They remove previously required fire rated shafts for certain piping configurations and allow residential systems to skip shaft ventilation where piping runs continuously without fittings. Another reason a general code summary is not a substitute for the adopted text.
EPA moved first, but EPA does not sign your mechanical inspection
EPA’s Technology Transitions rule under the AIM Act ended manufacture and import of R-410A residential and light commercial air conditioning and heat pump equipment as of January 1, 2025. That is why A2L equipment is what is on the shelf.
EPA regulates what may be manufactured, imported, sold, and installed. The mechanical code your jurisdiction adopted regulates how the equipment has to be installed and what an inspector signs off on. Those are separate systems on separate clocks, and the federal one moved first, which is also the context for the year EPA lifted the installation deadline on pre-2025 R-410A equipment.
Federal legality does not answer whether a local permit can be issued under the adopted mechanical code. Ask the jurisdiction before the crew is standing at the house with the replacement equipment.
One changeout can create three calls before the work is finished
During a code transition, the same job generates the same question from three directions in one afternoon: the tech on site, the supply house, and the homeowner who read something online. In call summaries this shows up as a cluster of short calls about one address rather than one clean question, and they land while every person who could answer is on a roof or in an attic.
A code transition does not add jobs. It adds phone calls per job. Permit questions, inspector callbacks, re-inspection scheduling, and homeowner questions about the new refrigerant all arrive during the workday, at a shop where everyone billable is already on a truck.
That is the narrow thing Dial 72 is for. It answers on the shop’s existing number, around the clock, and sends a call summary by text, so the office sees a permit question came in from the supply house without replaying a voicemail, and can book the re-inspection straight onto the calendar. The Starter plan is $95 a month. Whether that math works for your shop is a separate question, and what one missed no heat call actually costs is the number to run it against.
Get the adopted edition and the amendment text before the next changeout
Call the building department. Get the adopted edition and the adopting ordinance or rule in writing.
Read the local amendments and the transition provision. If the jurisdiction is still on an older edition, ask whether it adopted ICC’s A2L amendment package. Confirm the warning label, leak detection, lockout, and charge limit requirements that apply there.
Then decide in advance who answers the phone when the questions start arriving mid-job, and give that person the written code answer, the permit contact, and a process for re-inspection scheduling. Do not let a supply house label or the newest ICC book make the local installation decision for you.
