🌡️ Enter Saturation Temperature

R-454B is a zeotropic blend with ~0.7°F temperature glide. We show both dew point (vapor side) and bubble point (liquid side) pressures. Use dew point for suction calculations, bubble point for liquid line work.

40°F
°F

Evaporating: 30–50°F typical. Condensing: 100–130°F typical.

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Dew point pressure — updates live as you type
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Calculating R-454B pressure…

R-454B — The Refrigerant Replacing R-410A in New Systems

Every HVAC technician working on new systems needs to understand R-454B. Here’s what you need to know — in plain language.

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What Is R-454B?

R-454B (Puron Advance™, Opteon™ XL41) is a blend of 68.9% R-32 and 31.1% R-1234yf. It was chosen by most major US manufacturers — including Carrier, Trane, and Lennox — as the primary R-410A replacement for residential and light commercial air conditioners. It operates at similar pressures to R-410A and uses POE oil, making the transition fairly familiar for trained technicians.

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A2L — What Techs Need to Know

R-454B is classified A2L — non-toxic but mildly flammable. It has a low burning velocity and a high lower flammable limit. In practice, A2L refrigerants are far harder to ignite than propane or natural gas. However, A2L systems still require A2L-rated components, proper ventilation, and trained technicians. Never use open flames or cut into refrigerant lines without recovery. EPA 608 certification is required for purchase and service.

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Why the Switch? GWP 467 vs 2,088

R-410A has a GWP of 2,088. R-454B has a GWP of 467 — 78% lower. This is exactly why regulators required the change. The US EPA AIM Act mandated that new residential AC equipment must use refrigerants with GWP below 750 starting in 2025. R-454B comfortably meets this requirement. Existing R-410A systems can continue operating — the rules affect new equipment manufacturing, not existing systems.

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Temperature Glide Explained

R-454B has a temperature glide of about 0.7°F (0.4°C). This is the difference between the bubble point (where liquid starts boiling, liquid side) and the dew point (where the last liquid evaporates, vapor side). For HVAC service work, use dew point temperature for superheat calculations on the suction side. Use bubble point temperature for subcooling on the liquid line side. At 0.7°F glide, the practical impact is small.

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Pressures Similar to R-410A

R-454B runs at pressures about 3–8% lower than R-410A across the typical operating range. At 40°F evaporating, R-410A runs ~188 psig while R-454B runs ~178 psig. This close similarity means most R-410A manifold gauges and hoses work with R-454B. However, dedicated R-454B gauges are recommended for accurate saturation temperature readings without mental conversion.

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Service Best Practices

R-454B uses POE oil — same as R-410A. Never mix R-454B with R-410A or any other refrigerant. Contamination will degrade performance and may harm the compressor. Always charge R-454B as a liquid (not vapor) because it’s a blend — liquid charging preserves the blend composition. Charge by weight using a digital scale. Use A2L-rated recovery equipment. Leak detection sensors must be rated for A2L refrigerants.

📐 R-454B Saturation Equations and Key Formulas

Saturation pressure: uses Antoine/Wagner curve-fit to REFPROP R-454B data (valid −40°F to 150°F) Superheat (°F) = T_suction_actual − T_sat_dew_at_suction_pressure Subcooling (°F) = T_sat_bubble_at_condensing_pressure − T_liquid_line_actual Bubble point ≈ Dew point temperature + 0.7°F (at same pressure) psig = psia − 14.696  |  bar(g) = psig × 0.068948  |  kPa(abs) = psia × 6.89476

The pressure values in this calculator are derived from REFPROP data using a fitted Antoine-type equation. Accuracy is within ±0.5% from −40°F to 150°F (−40°C to 65°C). For critical applications, always cross-reference with the refrigerant manufacturer’s official PT chart published in the product data sheet.

Complete R-454B PT Chart Reference

Dew point saturation pressures at sea level. For bubble point (liquid line), add ~0.7°F to temperature at same pressure.

Temp (°F)Temp (°C)psig (dew)psia (dew)bar-g (dew)kPa absService Zone

Frequently Asked Questions About R-454B

R-454B is a refrigerant blend made of 68.9% R-32 and 31.1% R-1234yf. It’s sold under trade names including Puron Advance™ (Carrier) and Opteon™ XL41 (Chemours). Most major US HVAC manufacturers chose R-454B as their primary replacement for R-410A in residential and light commercial split systems. New equipment produced after January 2025 for the US market primarily uses R-454B. You’ll find it in new central AC units, heat pumps, and mini-splits from brands like Carrier, Bryant, Lennox, Heil, and others. It’s not used in existing R-410A systems — those continue to use R-410A for service.
At 40°F saturation (dew point), R-454B should be approximately 178 psig gauge pressure. This is the most common evaporating temperature reference point for residential AC systems under normal cooling load. The bubble point at 40°F is very close — about 177.3 psig. For comparison, R-410A at 40°F runs about 188 psig — so R-454B runs roughly 5% lower. If you’re using R-410A gauges on an R-454B system, the saturation temperature reading will be slightly off from the actual R-454B saturation value. Use this calculator or a dedicated R-454B gauge set for accurate readings.
No. R-454B is not a retrofit or drop-in replacement for R-410A systems. Existing R-410A equipment was not designed for A2L refrigerants and lacks the required safety features — A2L-rated contactors, sensors, and electrical components. Mixing R-454B with R-410A is never acceptable. If you have an existing R-410A system that needs service, continue using R-410A. R-410A remains available for servicing existing equipment. The transition to R-454B happens when you install brand-new equipment that was designed specifically for it.
Target values for R-454B are very similar to R-410A. For TXV or EEV-equipped systems, target suction line superheat of 8–12°F at the service valve under steady-state conditions. Liquid line subcooling should be 10–15°F at the condenser outlet. Fixed-orifice systems will run higher superheat — typically 15–25°F depending on load conditions. Always check the specific equipment manufacturer’s charging chart and instructions first, as different models may have different targets. Outdoor ambient temperature also affects the target superheat on some systems.
Yes, you need some updated equipment. Manifold gauges should ideally be rated for A2L refrigerants and scaled for R-454B (though standard hoses and manifolds typically work). Recovery equipment must be rated for A2L refrigerants — check the manufacturer’s label. Leak detectors must be rated for A2L/flammable refrigerants. Standard heated diode detectors designed for R-410A may not reliably detect R-454B. Do not use open flames for leak detection. Digital refrigerant analyzers and charging scales work the same. Your EPA 608 certification remains valid — no new certification is required just for A2L refrigerants.
R-454B is a zeotropic blend — its two components (R-32 and R-1234yf) have different boiling points. When R-454B changes phase, the two components evaporate and condense at slightly different rates, creating a temperature glide of about 0.7°F. The bubble point is where the liquid just begins to boil (liquid phase). The dew point is where the last drop of liquid evaporates (all vapor). The temperature difference between them is the glide. At 0.7°F, this is very small and rarely causes practical issues in field service work. For precision calculations, use dew point for superheat and bubble point for subcooling.
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