The Refrigerant Transition: HFCs, A2L and What the 608 Covers

The refrigerants in new equipment are changing, and the internet is full of confident claims about what that means for the 608. This article says only what official EPA pages and the regulation state, and marks where they stop.

Section 608 and substitutes: what applies

Substitute refrigerants are the ones that replaced ozone-depleting CFCs and HCFCs, such as HFCs. EPA's regulatory updates page explains how the 608 program came to cover them:

• November 18, 2016: EPA issued a final rule updating the refrigerant management regulations. It extended the program to substitutes such as HFCs, lowered the leak repair rates for equipment with 50 lb or more, extended the sales restriction to HFCs, and required recovery records for disposal of systems with 5 to 50 lb.
• January 1, 2018: the date from which the regulation's evacuation, safe disposal, technician certification and sales restriction sections apply to non-exempt substitutes (40 CFR 82.154, 82.155, 82.156, 82.161).
• February 26, 2020: EPA signed a rule rescinding the 2016 extension of the leak repair provisions to appliances using substitute refrigerants. Effective April 10, 2020, appliances with 50 lb or more of substitute refrigerants are no longer subject to the 82.157 leak repair, leak inspection, chronic leak reporting, retrofit or retirement, and related recordkeeping rules.

EPA states on the same page that the sales restriction, technician certification, safe disposal, evacuation, reclamation and certified recovery equipment requirements still cover HFCs and other substitutes, and that the Clean Air Act prohibition on intentionally venting or knowingly releasing refrigerants, including HFCs, still applies.

Source: EPA Section 608, regulatory updates, 40 CFR 82.154 and 40 CFR 82.157.

Exempt substitutes

Some substitutes are exempt from the venting prohibition and the other Subpart F requirements because EPA has determined their release does not pose a threat to the environment. 40 CFR 82.154(a) lists carbon dioxide, nitrogen and water in any application, ammonia in commercial or industrial process refrigeration or absorption units, and specific uses of hydrocarbons such as propane (R-290), isobutane (R-600a) and R-441A. Most of these exemptions are tied to specific uses, so "propane is exempt" is only true in the uses the rule lists.

The AIM Act: a separate program

EPA's background on HFCs and the AIM Act says HFCs are greenhouse gases with global warming potentials (GWPs) that can be hundreds to thousands of times more potent than carbon dioxide. The American Innovation and Manufacturing (AIM) Act was enacted on December 27, 2020. It gives EPA authority to phase down the production and consumption of listed HFCs, to manage HFCs and their substitutes, and to support the transition to new technologies through sector-based restrictions. The United States ratified the Kigali Amendment to the Montreal Protocol on October 26, 2022.

Technology Transitions

EPA's Technology Transitions program limits HFC use in specific sectors. EPA says that beginning January 1, 2025, manufacturers and importers of certain products and equipment that use HFCs must comply, with deadlines that vary by sector and subsector.

EPA's sector tables list a GWP limit of 700 for stationary residential and light commercial air conditioning and heat pumps. For self-contained products such as window units, the manufacture and import compliance date is January 1, 2025. For systems such as mini-splits and unitary systems, the tables give an installation compliance date of January 1, 2025, with no installation compliance date for systems whose specified components were all manufactured or imported before January 1, 2025. For variable refrigerant flow systems the installation date is January 1, 2027, with a limited exception to 2028. EPA notes the tables are informational and points to 40 CFR Part 84, Subpart B for the full rule.

Emissions Reduction and Reclamation

EPA published a final rule to manage certain HFCs and their substitutes on October 11, 2024, linked from the Section 608 home page. EPA's regulatory actions page lists what it covers, including leak repair for certain appliances, automatic leak detection for certain new and existing appliances, a standard for reclaimed HFCs, servicing with reclaimed HFCs, and recovery from disposable cylinders before disposal. EPA describes these leak repair requirements as applying to appliances with a charge of 15 lb or more that contain an HFC or certain HFC substitutes (40 CFR 84.106). This is AIM Act regulation, not the 608 leak repair rule in 82.157.

Where A2L appears on official EPA pages

A2L is an ASHRAE safety classification. On EPA's SNAP page for residential and light commercial air conditioning and heat pumps, the ASHRAE designation column shows A2L for HFC-32, R-452B, R-454A, R-454B, R-454C and R-457A, listed as acceptable with use conditions. The page says substitutes are reviewed for factors including toxicity, flammability and exposure potential, and refers to the rule for the detailed use conditions.

The Section 608 pages we checked, including the test topics page, do not use the term A2L. The Core topics include "Substitute Refrigerants and oils" and "Safety," and each technical type includes Safety, but EPA does not publish the questions or say whether A2L handling is on the test. Ask your certifying organization what its current study material covers.

What to take into the exam

• Most 608 rules apply to non-exempt substitutes as well as to CFCs and HCFCs.
• The 82.157 leak repair rules apply only to ozone-depleting refrigerants since April 10, 2020. A question with an HFC-only system and the 10, 20 and 30 percent rates is testing whether you know that.
• Exempt substitutes are exempt only in the listed uses.
• AIM Act rules (GWP limits, ER&R leak repair at 15 lb) are real, but they are a different program from the 608 regulation.

For the leak rates themselves, see the Type II guide.

Frequently asked questions

Does Section 608 apply to HFC refrigerants?

Yes, for most rules. EPA says the sales restriction, technician certification, safe disposal, evacuation, reclamation and certified recovery equipment requirements cover HFCs and other substitutes. The venting prohibition applies too. The 40 CFR 82.157 leak repair rules do not apply to appliances containing only substitutes since April 10, 2020.

Is A2L covered on the EPA 608 exam?

EPA's Section 608 test topics list includes Substitute Refrigerants and oils and Safety, but the Section 608 pages we checked do not use the term A2L. Ask your certifying organization what its current test and study material cover.

Which refrigerants are listed as A2L by EPA?

On EPA's SNAP page for residential and light commercial air conditioning and heat pumps, the ASHRAE designation column shows A2L for HFC-32, R-452B, R-454A, R-454B, R-454C and R-457A, listed as acceptable with use conditions.

What GWP limit applies to new residential AC systems?

EPA's Technology Transitions sector tables list a GWP limit of 700 for residential and light commercial air conditioning and heat pump systems, with compliance dates and exceptions given there and in 40 CFR Part 84, Subpart B.