2.4 AIM Act and HFC Phasedown Schedule

The Most Important Modern Rule

The American Innovation and Manufacturing (AIM) Act, signed into law in December 2020, is the biggest change to U.S. refrigerant regulation since the original CFC phaseout. It is the domestic law that implements the Kigali Amendment's HFC phasedown. As of 2026 it is actively reshaping the HVAC/R industry, so it is heavily tested. The AIM Act gives EPA three distinct authorities, each tested separately:

1. Phase down HFC production and consumption (subsection e).
2. Manage HFCs — maximize reclamation, minimize releases, and require leak repair (subsection h).
3. Restrict HFC use in specific sectors via Technology Transitions (subsection i).

Why HFCs Are Now Regulated Like ODS

HFCs have zero ozone depletion potential, so the original Montreal/Clean Air Act ozone rules did not reach them. But their global warming potential is enormous — hundreds to thousands of times that of CO2. The AIM Act closes that gap, subjecting HFCs to production caps, leak-repair duties, and recovery requirements that mirror the old ODS regime. The practical upshot for technicians: treat an HFC exactly as carefully as you treated R-22 — no venting, full recovery, leak repair, and recordkeeping.

The HFC Phasedown Schedule

The AIM Act mandates a phasedown (gradual reduction), not a phaseout (complete elimination). Production and consumption step down against a historic baseline:

The target everyone cites is 85% reduction by 2036 — but 15% of baseline production continues indefinitely to service legacy equipment. That "phasedown, not phaseout" distinction is a frequent exam trap.

Allowance Allocation

EPA enforces the cap through allowances. Each year EPA issues a limited pool of production and consumption allowances; a company must hold allowances to legally produce or import HFCs. Critically, allowances are denominated in exchange value, which equals each HFC's 100-year GWP. So producing one metric ton of a high-GWP refrigerant (e.g., R-404A, GWP 3,922) consumes far more allowances than one ton of a low-GWP refrigerant. This design economically pushes the market toward low-GWP options. EPA re-issues the allowance allocation annually — for example, EPA published the 2026 allowance allocations in late 2025.

Technology Transitions: GWP Limits by Sector

Under subsection (i), EPA's Technology Transitions rule sets maximum GWP values for refrigerants used in new equipment, by sector. These do not force you to rip out existing systems — they restrict what can be manufactured, imported, or installed new:

What This Means for a Technician in 2026

1. R-410A (GWP 2,088) exceeds the 700 limit, so it is being designed out of new residential/commercial AC. New systems use R-454B (GWP 466) and R-32 (GWP 675).
2. Existing R-410A systems are NOT affected — you may still service, repair, and recharge them.
3. R-22 remains in legacy equipment, but no new R-22 has been produced or imported since January 1, 2020, so only reclaimed/recycled R-22 is available.
4. The new low-GWP refrigerants are A2L (mildly flammable), requiring updated handling, leak-detection, and ventilation practices (covered in Section 1.5).

The HFC Leak Repair / Refrigerant Management Rule

Under subsection (h), EPA's Refrigerant Management rule extends ODS-style leak-repair and recovery duties to HFC appliances. The headline number: it applies to appliances with a refrigerant charge of 15 pounds or greater — far below the old 50-lb threshold that governed comparable ODS systems. Owners/operators of covered systems must track refrigerant additions, repair leaks that exceed trigger rates within set timeframes, and — for the largest commercial systems — may need automatic leak detection. These requirements phase in around 2026–2027.

For the Exam: Memorize the phasedown steps (60% in 2024, 30% in 2029, 15%/85% reduction by 2036); know it is a phasedown, not a phaseout; know the 700 GWP cap for new residential/commercial AC (since 2025) and the 15-lb HFC leak-repair threshold; and understand allowances are tied to GWP/exchange value.

Worked Example: Why Allowances Punish High-GWP Refrigerants

Consider a producer choosing whether to make a ton of R-404A (GWP 3,922) or a ton of R-32 (GWP 675). Because allowances are measured in exchange value (GWP), the R-404A ton consumes roughly 5.8× as many allowances as the R-32 ton (3,922 ÷ 675 ≈ 5.8). As the total allowance pool shrinks each phasedown step, high-GWP products become disproportionately expensive to make. This is the mechanism — not an outright ban — that drives the market toward R-32, R-454B, and HFO blends. It also explains why R-404A is one of the very first refrigerants squeezed out of new production.