Why the Refrigerant Industry Is Changing Again
The EPA's AIM (American Innovation and Manufacturing) Act is mandating a phasedown of high-GWP (Global Warming Potential) HFCs including R-410A. Beginning January 1, 2025, new residential HVAC equipment manufactured in the US must use refrigerants with a GWP below 700. R-410A has a GWP of 2,088 - nearly three times the new limit. R-454B and R-32 are the two primary replacements entering the market.
R-454B (Puron Advance° by Carrier)
R-454B is a binary HFO/HFC blend (68.9% R-32, 31.1% R-1234yf). It has a GWP of 466 - well below the 700 threshold. Carrier, Bryant, Payne, and ICP brands are transitioning their new residential equipment to R-454B.
R-454B Key Properties
| Property | R-454B | R-410A (for comparison) |
|---|---|---|
| GWP (AR4) | 466 | 2,088 |
| Safety classification | A2L (mildly flammable) | A1 (non-flammable) |
| Boiling point | -51.6°F (-46.4°C) | -61.9°F (-52.2°C) |
| Critical temperature | 175.3°F (79.6°C) | 160.9°F (71.6°C) |
| Oil type | POE | POE |
| Cylinder color | Medium blue (proposed) | Rose/pink |
R-454B Pressure/Temperature Chart
| Temp °F | Temp °C | Dew Point (PSIG) | Bubble Point (PSIG) |
|---|---|---|---|
| 0 | -18 | 43.8 | 40.5 |
| 20 | -7 | 79.4 | 74.8 |
| 30 | -1 | 101.8 | 96.2 |
| 40 | 4 | 128.7 | 121.9 |
| 50 | 10 | 160.5 | 152.5 |
| 60 | 16 | 197.5 | 188.3 |
| 70 | 21 | 240.2 | 229.5 |
| 80 | 27 | 289.0 | 276.7 |
| 90 | 32 | 344.3 | 330.2 |
| 100 | 38 | 406.8 | 391.0 |
| 110 | 43 | 476.8 | 459.1 |
| 120 | 49 | 555.0 | 535.2 |
| 130 | 54 | 641.8 | 619.7 |
R-454B is a zeotropic blend - it has both bubble and dew points (temperature glide). Use dew point for suction line and bubble point for liquid line calculations.
R-32 (Difluoromethane)
R-32 is a pure single-component HFC with a GWP of 675. It is widely used in mini-split systems from Daikin, Mitsubishi, Fujitsu, and LG. R-32 has higher energy efficiency than R-410A and is already the dominant refrigerant in mini-splits sold in Asia and Europe. Unlike R-454B, R-32 has no temperature glide.
R-32 Key Properties
| Property | R-32 | R-410A (for comparison) |
|---|---|---|
| GWP (AR4) | 675 | 2,088 |
| Safety classification | A2L (mildly flammable) | A1 (non-flammable) |
| Boiling point | -61.1°F (-51.7°C) | -61.9°F (-52.2°C) |
| Cylinder pressure at 77°F | ~185 PSIG | ~210 PSIG |
| Oil type | POE | POE |
| Temperature glide | None (pure refrigerant) | None |
R-32 Pressure/Temperature Chart
| Temp °F | Temp °C | Pressure (PSIG) |
|---|---|---|
| -20 | -29 | 11.3 |
| 0 | -18 | 28.8 |
| 20 | -7 | 56.3 |
| 30 | -1 | 74.2 |
| 40 | 4 | 96.2 |
| 50 | 10 | 122.3 |
| 60 | 16 | 152.8 |
| 70 | 21 | 188.2 |
| 80 | 27 | 228.8 |
| 90 | 32 | 275.1 |
| 100 | 38 | 327.5 |
| 110 | 43 | 386.3 |
| 120 | 49 | 452.0 |
| 130 | 54 | 524.9 |
A2L Safety: What Technicians Need to Know
Both R-454B and R-32 are classified A2L - meaning low toxicity but mildly flammable. The "2L" indicates slow flame speed (<10 cm/s). This is very different from propane (A3) or isobutane - A2L refrigerants will not burn in open air under normal conditions and require a specific ignition energy to combust.
Key A2L Safety Requirements
- No open flames or arc ignition in a confined space when working with A2L refrigerants
- A2L-rated recovery equipment required - standard R-410A recovery machines are not rated for A2L
- A2L-rated leak detectors required - not all R-410A detectors respond to R-32 or R-454B
- Ventilate before and during work in tight mechanical rooms or enclosed spaces
- Equipment is A2L-designed from factory - motors, controls, and enclosures meet IEC 60335-2-40 requirements for A2L use
- A2L refrigerants cannot be retrofitted into existing R-410A equipment - the equipment itself must be rated for A2L
Tooling Requirements for 2025+ Equipment
| Tool | R-410A Compatible | A2L Compatible |
|---|---|---|
| Recovery machine | Standard | Must be A2L rated |
| Manifold gauges | R-410A gauges (800 PSI) | A2L rated manifolds |
| Leak detector | HFC detector | Must detect R-32/HFO blends |
| Vacuum pump | Standard | Standard (no combustion risk in vacuum) |
| Scale | Standard | Standard |
Transition Timeline
- January 1, 2025: New residential and light commercial HVAC equipment must use refrigerants with GWP <700
- Existing R-410A equipment: Can be serviced with R-410A indefinitely - the phasedown applies to new equipment manufacture only
- R-410A availability: Will decrease in supply over 2025-2033 phasedown schedule - expect prices to rise
- Technician certification: EPA 608 certification still required. Additional A2L safety training is now strongly recommended