The AIM Act and the HFC Phase-Down
R-410A is on its way out. Here is what the AIM Act actually requires, why it is pushing the entire industry toward low-GWP A2L refrigerants like R-454B, and what changes on your truck and at the jobsite.
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In This Guide
What the AIM Act Actually Is
The American Innovation and Manufacturing Act — the AIM Act — was signed into law in December 2020 and gave the EPA authority to phase down the production and consumption of hydrofluorocarbons (HFCs). HFCs are the refrigerants that replaced the old ozone-depleting R-22. They do not hurt the ozone layer, but they are extremely potent greenhouse gases, and that is the problem the AIM Act is designed to solve.
It is important to understand the distinction from the R-22 phase-out. R-22 was an HCFC removed under the Montreal Protocol because it damaged the ozone layer. HFCs like R-410A are being phased down under the AIM Act because of their climate impact. Same idea for a tech in the field — the primary refrigerant you charge every day is being legislated away — but a different law and a different reason.
The AIM Act does this three ways: a stepped-down cap on how many HFCs can be produced or imported each year, restrictions on using high-GWP refrigerants in specific new equipment, and rules that push the industry toward reclaim and better leak management. For you, the most consequential piece is the second one: as of January 1, 2025, new residential and light commercial air conditioners and heat pumps must use a refrigerant with a GWP under 700.
Bottom line: R-410A has a GWP of roughly 2,088. It does not meet the sub-700 limit, so manufacturers can no longer build new residential/light commercial systems around it. That single number is why your supply house is now full of R-454B and R-32 equipment.
GWP: The Number That Drives Everything
Global Warming Potential (GWP) measures how much heat a gas traps in the atmosphere compared to carbon dioxide over a 100-year period. CO2 is the baseline at 1. When a refrigerant has a GWP of 2,088, it means one pound leaked has roughly the same 100-year warming impact as 2,088 pounds of CO2.
That is why the EPA drew the line at 700. Refrigerants below that threshold cut the climate impact of an equipment leak by more than two-thirds compared to R-410A. The catch is chemistry: almost every refrigerant that gets under 700 does so by becoming mildly flammable. That trade-off is the entire story of the transition, and it is why the safety-class discussion matters as much as the GWP number.
| Refrigerant | Type | GWP | Safety Class | Status |
|---|---|---|---|---|
| R-22 | HCFC | 1,810 | A1 | Phased out (2020) |
| R-410A | HFC blend | 2,088 | A1 | New equip. ban Jan 2025 |
| R-32 | HFC | 675 | A2L | Active, growing |
| R-454B | HFC/HFO blend | 466 | A2L | New US standard (2025) |
| R-404A | HFC blend | 3,922 | A1 | Being phased down |
| R-290 | Propane | 3 | A3 | Growing (small charge) |
Reading an ASHRAE 34 Safety Class
The letter is toxicity (A = lower, B = higher). The number is flammability: 1 = no flame propagation, 2L = mildly flammable with low burning velocity, 2 = flammable, 3 = highly flammable. So R-454B is A2L: low toxicity, mildly flammable. It will burn, but only with a sustained ignition source and a specific concentration — it is a world apart from A3 propane.
The Phase-Down Timeline
The AIM Act does not shut off R-410A overnight. Production steps down on a schedule, which means service refrigerant stays available for years — but at a rising price. Here is the practical timeline for the R-410A phase-down:
Manufacturing ban on new R-410A residential and light commercial AC/heat pumps. New systems must use a refrigerant with GWP < 700.
Transition period. R-410A remains available for service, but overall HFC production keeps stepping down and prices climb.
A large step-down in the HFC cap — roughly a 40% reduction from baseline. Expect R-410A to get noticeably tighter and more expensive.
Continued phase-down. R-410A shifts toward a legacy, service-only product. Reclaimed refrigerant becomes a bigger part of the supply.
Minimal new R-410A production. Service supply leans heavily on reclaim, similar to how R-22 works today.
Field reality: You will be servicing R-410A systems well into the 2030s — a system installed in 2024 has a 15-plus-year life. Stop scrapping recovered R-410A. Reclaim it. As new production shrinks, the cylinder in your recovery machine becomes genuinely valuable, and clean reclaimed R-410A is what keeps existing systems running.
The Low-GWP Replacements
Two refrigerants dominate the residential and light commercial transition, and it helps to know why manufacturers chose them.
R-454B (GWP 466)
A blend of R-32 and R-1234yf. This is the designated R-410A replacement for most US residential and light commercial equipment — Carrier, Trane, and others standardized on it.
- Operating pressures within ~3% of R-410A
- Slightly higher COP (efficiency)
- Near drop-in behavior for the tech, A2L rules apply
R-32 (GWP 675)
A single-component refrigerant, not a blend — so it does not fractionate and can be charged as vapor or liquid without composition worry. Common in mini-splits and used by Daikin, LG, and others.
- Higher discharge temps than R-410A
- Single component — no glide, no fractionation
- Also A2L, same safety handling
The good news for a working tech: R-454B behaves so much like R-410A on the gauges that your diagnostic instincts still apply. At a 95°F outdoor ambient you will still see high-side pressures in the same ballpark, and superheat/subcooling targets are read the same way — you just use the R-454B PT chart instead of the R-410A one. The refrigerant changed; the physics of the vapor-compression cycle did not.
Do not mix or "top off" across refrigerants
Never add R-454B to an R-410A system or vice versa, and never charge a blend as vapor when the manufacturer specifies liquid. Cross-charging destroys system performance, voids warranties, and contaminates recovery cylinders. One refrigerant per system, matched to the nameplate — no exceptions.
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Working With A2L Refrigerants
This is where the transition changes your day-to-day. A2L refrigerants are mildly flammable, so codes (UL 60335-2-40, ASHRAE 15/34, and the updated model mechanical codes) build in layers of protection. Most of it is handled by the equipment, but you have to respect it in the field.
- Leak detection built in. Many A2L systems include a factory refrigerant sensor that triggers the blower to dilute a leak. Do not defeat it, and follow the OEM procedure if it faults.
- A2L-rated tools. Use recovery machines, gauges, and leak detectors rated for A2L. Your recovery machine and vacuum pump should be A2L-listed with the proper internal spark protection.
- No open flames near a charge. Keep ignition sources away when a system is open. Prefer nitrogen purge and press fittings or a proper brazing setup with the area cleared and ventilated.
- Charge-limit and room-size rules. A2L equipment has maximum charge limits tied to the size of the conditioned space. Undersized rooms may require additional mitigation — check the OEM install manual.
- Dedicated cylinders and color. A2L cylinders carry a red band and left-hand threads on the valve. Keep recovery cylinders refrigerant-specific.
- Ventilation on recovery. Recover in a ventilated space; a pooled A2L leak in a low, unventilated area can reach a flammable concentration.
Your EPA 608 still covers you
There is no separate federal A2L certification — your existing EPA Section 608 certification still applies to handling, recovery, and recordkeeping. But manufacturers and many employers now require A2L safety training before you touch the equipment, and it is genuinely worth taking. Know the material before your first R-454B changeout, not during it.
Field Transition Checklist
A practical order of operations as A2L equipment becomes the default install:
Step 1: Verify the nameplate.
Confirm the refrigerant type before doing anything. Grab the matching PT chart and target superheat/subcooling for that exact refrigerant — never assume R-410A numbers.
Step 2: Confirm your tools are A2L-rated.
Recovery machine, vacuum pump, leak detector, and gauges all listed for A2L. Cylinders dedicated to the correct refrigerant.
Step 3: Clear and ventilate the work area.
Remove ignition sources, ensure airflow, and locate the equipment's built-in leak sensor so you know how it behaves.
Step 4: Evacuate, charge, and verify by weight.
Pull a proper vacuum, weigh in the factory charge, then trim to target subcooling. Charge blends like R-454B as liquid to preserve composition.
Step 5: Recover and reclaim old refrigerant.
On R-410A changeouts, recover cleanly and send it to reclaim. Log it — recordkeeping matters more as production tightens.
Pro tip: dial in charge by subcooling
With R-454B and R-32, the fastest way to confirm a good charge on a TXV system is subcooling at the liquid line, verified against the manufacturer's target (commonly 8–12°F). Weighing in the factory charge gets you close; subcooling confirms it. Ventora's superheat/subcooling calculator will pull the right saturation temp for whatever refrigerant is on the nameplate.
Common Questions
Can I still buy and use R-410A?
Yes — for service. The 2025 ban is on manufacturing new R-410A equipment, not on servicing the millions of systems already installed. Expect the price to keep climbing as production steps down.
Is R-454B a drop-in for R-410A?
No. It behaves similarly on the gauges, but it is a different refrigerant for different, purpose-built equipment. Never charge R-454B into a system designed for R-410A. Match the nameplate.
Do I need a new EPA certification for A2Ls?
No separate federal cert exists — your EPA 608 still applies. But most OEMs and employers require A2L safety training, and A2L-rated tools are a must.
What about R-32 versus R-454B?
Both are A2L and both meet the sub-700 limit. R-454B is the dominant US ducted-system replacement; R-32 is common in mini-splits and global markets. Service each per its own PT chart and OEM spec.
Stay Ahead of the Refrigerant Transition
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