R-454B vs R-410A: Full Pressure & Property Comparison
If you're an HVAC technician, you're about to see a lot more R-454B and a lot less R-410A. The EPA's AIM Act is forcing the switch — but how different are these two refrigerants in the field? This guide compares pressures, properties, safety, and practical considerations so you know exactly what changes (and what doesn't) when you move from R-410A to R-454B.
Quick Comparison
| Property | R-454B | R-410A | Difference |
|---|---|---|---|
| GWP | 466 | 2088 | −78% |
| ODP | 0 | 0 | Same |
| Safety Class | A2L (mildly flammable) | A1 (non-flammable) | ⚠️ Different |
| Glide | 2.0°F | 0.2°F | +1.8°F |
| Composition | 68.9% R-32 / 31.1% R-1234yf | 50% R-32 / 50% R-125 | — |
| Oil | POE | POE | Same type |
| Discharge Temp | Lower | Higher | Better for R-454B |
| Critical Temp | 168°F | 163°F | +5°F |
Pressure Comparison: R-454B vs R-410A
R-454B runs about 5% higher pressure than R-410A at the same saturated temperature. The pressures are close, which is why R-454B is sometimes called a "near-drop-in" — but the equipment is NOT interchangeable.
| Temp (°F) | R-454B Bubble (PSIG) | R-410A Bubble (PSIG) | Difference |
|---|---|---|---|
| 0°F | 27.6 | 23.0 | +20% |
| 20°F | 82.0 | 78.0 | +5% |
| 40°F | 124.0 | 118.0 | +5% |
| 70°F | 211.0 | 201.0 | +5% |
| 90°F | 288.0 | 274.0 | +5% |
| 110°F | 383.0 | 365.0 | +5% |
| 130°F | 500.0 | 476.0 | +5% |
| 150°F | 640.0 | 608.0 | +5% |
R-454B data: Honeywell Solstice® PT chart. R-410A data: Arkema Forane® PT chart.
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Download Free →The Big Difference: Safety Class (A2L vs A1)
This is the single most important difference for field techs.
A2L means R-454B is lower flammability with a lower burning velocity (≤10 cm/s). In practical terms:
- R-454B will burn under specific conditions (high concentration + ignition source)
- It's much harder to ignite than R-290 (propane) or even A2/A3 refrigerants
- Most service practices remain the same, but follow A2L-safe procedures
- Equipment must be designed and labeled for A2L use
⚠️ Important: Do NOT install R-454B in equipment designed only for A1 (non-flammable) refrigerants. A2L systems have specific safety features: leak detection sensors, modified electrical components, and ventilation requirements. Using the wrong refrigerant is a code violation and safety hazard.
Temperature Glide: Why It Matters
R-410A is nearly azeotropic — it behaves almost like a single refrigerant. R-454B is a zeotropic blend with a 2°F temperature glide.
What this means in practice:
- R-410A: One saturation temperature at each pressure. Simple.
- R-454B: Two saturation temperatures at each pressure — bubble point and dew point differ by ~2°F.
Which value to use?
| Measurement | Use | Why |
|---|---|---|
| Superheat (evaporator) | Dew point | Vapor side |
| Subcooling (condenser) | Bubble point | Liquid side |
Using the wrong curve introduces a ~2°F error. For precise charging, always check which curve your PT chart or app uses.
Oil Compatibility
Both R-454B and R-410A use POE (polyol ester) oil. However:
- Not all POE oils are the same viscosity or additive package
- Always use the OEM-specified POE lubricant
- Do not mix oils across systems
- When converting a system (rare — usually only new equipment), follow manufacturer's retrofit procedure
The R-410A Phase-Out Timeline
What This Means for HVAC Techs
You'll work with both for years
R-410A systems aren't disappearing overnight. You'll service existing R-410A equipment for 10-15 more years while also installing and servicing new R-454B systems. You need PT data for both.
Service tools are mostly compatible
- Manifold gauges: R-410A-rated gauges handle R-454B pressures (slightly higher but within range)
- Recovery cylinders: Use DOT-approved cylinders, never mix refrigerants
- Vacuum pumps: Same requirements
- Leak detectors: Some R-410A leak detectors may not detect R-454B — check compatibility
Training requirements
Many jurisdictions now require A2L-specific safety training. Check your local codes and EPA Section 608 certification requirements for updates.
🚫 Never mix refrigerants. Mixing R-454B and R-410A in the same system creates unpredictable pressures, temperatures, and safety risks. Always recover fully before charging with a different refrigerant. Cross-contaminated refrigerant cannot be reclaimed and must be destroyed.
Frequently Asked Questions
Can I use R-454B in an R-410A system?
No. R-454B is not a drop-in replacement. Although pressures are similar, R-454B is an A2L mildly flammable refrigerant and requires equipment designed for A2L service. Never mix the two.
Why is R-410A being phased out?
R-410A has a GWP of 2088, too high under the EPA AIM Act. Starting January 2025, R-410A production was cut significantly, pushing manufacturers to lower-GWP alternatives like R-454B (GWP 466).
Are the pressures the same?
Close but not identical. R-454B runs about 5% higher than R-410A. At 110°F, R-454B is 383 PSIG vs R-410A at 365 PSIG. R-410A-rated tools generally handle R-454B, but confirm with the manufacturer.
What oil does R-454B use?
R-454B uses POE (polyol ester) oil, same type as R-410A. But always use the OEM-specified POE lubricant — not all POE oils are interchangeable.
Do I need new gauges for R-454B?
Most R-410A-rated manifold gauges will handle R-454B pressures (slightly higher but within range). However, check that your leak detector is compatible with R-454B and that you have dedicated hoses to avoid cross-contamination.
📱 Carry both PT charts in your pocket
FieldCalc HVAC includes R-454B, R-410A, R-32, and 10 more refrigerants — all offline. Switch between refrigerants with one tap. Free to download.
Download for iOS →Data Sources
- Honeywell Solstice® R-454B PT Chart (PDF)
- Chemours Opteon™ R-454B technical documentation
- Arkema Forane® R-410A PT Chart (PDF)
- NIST Reference Fluid Properties (Refprop)
- EPA AIM Act Final Rule (October 2023)
- ASHRAE Standard 34 — Refrigerant Safety Classification
This comparison is for field reference only. Always follow OEM specifications, local codes, and EPA regulations.