A2L/Crosswalk
A2L/Crosswalk

Refrigerant quick reference

R-22, R-410A, R-32 and R-454B side by side: what is in each one, safety class, GWP, and where it stands today.

Checked against the sources below on October 7, 2026

The short answer

New residential equipment runs on R-32 or R-454B. Both are class A2L — lower toxicity, mildly flammable — and both are for new equipment only. They are not interchangeable with each other or with R-410A. The refrigerant on the nameplate is the only one that goes in that unit.

Side by side

R-22

HCFC · single compound
A1
What is in it
HCFC-22 (chlorodifluoromethane)
GWP
1,810
Ozone depletion
0.055

No production or import in the U.S. since January 1, 2020. Existing equipment can stay in service on recovered, reclaimed or previously produced refrigerant.

R-410A

HFC blend
A1
What is in it
50% R-32 · 50% R-125
GWP
2,088
Ozone depletion
0

Above the 700 GWP limit. Since January 1, 2025 it can go into a new residential system only if every specified component was made or imported before that date. Components for servicing existing systems are still made.

R-32

HFC · single compound
A2L
What is in it
HFC-32 (difluoromethane)
GWP
675
Ozone depletion
0

Listed by EPA as acceptable, subject to use conditions, for new residential and light commercial air conditioners and heat pumps. New equipment only — never a retrofit.

R-454B

HFC / HFO blend
A2L
What is in it
68.9% R-32 · 31.1% R-1234yf
GWP
465
Ozone depletion
0

Listed by EPA as acceptable, subject to use conditions, for new residential and light commercial air conditioners and heat pumps. New equipment only — never a retrofit.

Why you see 465, 466 and 470 for R-454B

They are the same refrigerant counted three ways. EPA’s table for the 700 GWP limit says 465 (it counts the R-1234yf part as 1). 466 comes from an older value for R-1234yf, and 470 is a rounded figure — the one EPA’s SNAP page and the ENERGY STAR product list print. All three are far below 700.
What the refrigerants are made ofComposition bars for R-22 (single HCFC, A1, GWP 1,810), R-410A (50% R-32 and 50% R-125, A1, GWP 2,088), R-32 (single HFC, A2L, GWP 675), R-454B (68.9% R-32 and 31.1% R-1234yf, A2L, GWP 466) and R-1234yf (single HFO, A2L, GWP 4). Removing the R-125 half of R-410A lowers GWP and brings back mild flammability.WHAT THE REFRIGERANTS ARE MADE OFcomposition by mass · safety class · global warming potential (GWP, AR4)classGWPR-22HCFC · 1st generationR-22ozone-depleting (ODP 0.05) · production ended Jan 1, 2020A11,810R-410AHFC blend · 2nd generationR-32 50%R-125 50%the R-125 half kills the flame — and carries most of the GWPA12,088R-32single HFC · 3rd generationR-32 100%zero glide · runs ~2–3% higher pressure than R-410AA2L675R-454BHFC/HFO blend · 3rd generationR-32 68.9%R-1234yf 31.1%~2–2.7 °F glide (varies with pressure) · runs ~3–5% below R-410AA2L466R-1234yfHFO, single componentR-1234yf 100%cars and light trucks (EPA 609 world), not residentialA2L4R-32 (HFC)R-125 (HFC — suppresses the flame, high GWP)R-1234yf (HFO)HCFC (R-22)Take the R-125 out of R-410A and two things happen: the GWP drops, and the flame comes back.
What each refrigerant is made of. Take the R-125 out of R-410A and two things happen: the GWP drops, and the flammability comes back. (The drawing uses the older 466 figure for R-454B.)

What A1 and A2L mean

The safety class is two characters. The letter is toxicity — A is lower, B is higher. The number is flammability — 1 is no flame propagation, 2L is lower flammability, 2 is flammable, 3 is higher flammability. R-410A and R-22 are A1. R-32 and R-454B are A2L.

ASHRAE 34 refrigerant safety classificationA grid of toxicity (A lower, B higher) by flammability (1 none, 2L lower, 2 flammable, 3 higher). R-410A, R-134a and R-22 are A1. R-32, R-454B and R-1234yf are A2L: they burn, slowly. R-290 propane is A3. R-717 ammonia is B2L.ASHRAE 34 SAFETY CLASSletter = toxicity · number = flammabilityAlower toxicityBhigher toxicity1no flame propagationR-410AR-134aR-22R-1232Llower flammabilityR-32R-454BR-1234yfR-717 ammonia2flammableR-152a—3higher flammabilityR-290 propaneR-600a isobutane—the class thatchanged the tradenew systems since 20252L is not "non-flammable". It burns, slowly, with low energy — which is exactly why it needs leak detection,charge limits and A2L-rated tools. R-32 and R-454B are both 2L and are still not interchangeable with each other.
The safety classification grid. The dashed row is the class new residential equipment moved into.

A2L is not “non-flammable”

It burns — slowly, with low energy. That is exactly why the equipment carries a fire warning label and why the rule limits how much refrigerant a unit may hold for the size of the room it serves.

What EPA requires of A2L equipment

R-32 and R-454B are listed as acceptable subject to use conditions. These are the conditions written into the rule — what the equipment must have, not a procedure for working on it.

ConditionWhat the rule says
New equipment onlyNone of these refrigerants may be used as a conversion or “retrofit” refrigerant for existing equipment designed for other refrigerants.
Safety standardThe equipment must meet UL 60335-2-40, 3rd edition (November 1, 2019). EPA proposed moving to the 4th edition in November 2025; that proposal is not final.
Charge limitThe charge must not exceed the maximum refrigerant mass that standard allows for the room size where the equipment is used.
Red markingService ports, pipes, hoses and other devices the refrigerant passes through must be marked red (PMS #185 or RAL 3020), extending at least 1 inch in both directions, and the marking must be replaced if removed.
Warning labelsOn the outside of the equipment: “WARNING—Risk of Fire. Flammable Refrigerant Used. To Be Repaired Only By Trained Service Personnel. Do Not Puncture Refrigerant Tubing.” Lettering at least 1/4 inch high.
On the indoor unitNear the nameplate: the minimum installation height and the minimum room area.

The rule also notes that recovery equipment should be designed for flammable refrigerants, that recovered flammable refrigerant is likely to be hazardous waste under RCRA, and that DOT requirements for transporting flammable gases apply.

On the cylinder

A2L supply cylinder and A2L recovery cylinderLeft: an A2L refrigerant supply cylinder painted uniform light gray-green with a red band on the shoulder marking a flammable class, a printed label as the only identifier, and a left-hand-thread valve. Right: an A2L recovery cylinder with a gray body, yellow top and a resettable pressure-relief valve. The same flame pictogram appears on equipment nameplates.READING AN A2L CYLINDERthe paint no longer tells you the refrigerant — the label does; the red band tells you it burnsvalve · left-hand threadR-454Brefrigerant · 20 lbA2Lmildlyflammablekeep away from ignitionGWP 466 · ASHRAE A2LSUPPLY CYLINDERRED BAND = flammable class2L, 2 or 3 — a warning, not an identityTHE LABEL is the identifierread it every time; A2Ls look alikePAINT: uniform gray-greensince 2020 — pink R-410A and green R-22 are goneRECOVERYrated for flammablesRECOVERY CYLINDERyellow topgray bodyresettable PRVnot a rupture discSame flame on the nameplate. Cylinder, equipment and gauge scale must all agree — a trained technician's check, not yours yet.
How an A2L cylinder is marked. The label identifies the refrigerant; the color no longer does.
  • The label is the identifier. Federal rules require every container of an HFC to be labeled with the name of what is inside, and the percentages if it is a blend.
  • The red band is an industry convention. EPA’s rule points to an AHRI guideline as its origin. What federal rules require red is the marking on the equipment, described above.
  • In transport, R-32 is a Division 2.1 flammable gas (UN3252). R-22 is Division 2.2, non-flammable.

Who can buy and handle them

The same federal certification covers all of them. EPA Section 608 applies to any non-exempt substitute refrigerant, and R-32 and R-454B are not exempt: only a certified technician (or an employer of one) can buy them, and venting them is prohibited. There is no separate federal A2L certificate — the rule advises that only technicians trained in flammable refrigerants should service this equipment. EPA 608 at a glance →

Sources

Federal rules change. This page reports what the sources said on the date above; the source is the authority, and state or local rules can be stricter. It is reference material, not legal advice and not installation guidance.