R454B RefrigerantR32 / R1234yf blend · Lower-GWP R410A-class option
R454B is a zeotropic blend of approximately 68.9% R32 and 31.1% R1234yf by mass. It is used in new air-conditioning, heat-pump and selected chiller platforms designed for A2L refrigerants. The U.S. EPA Technology Transitions reference table assigns R454B a 100-year GWP of 465.
What is R454B refrigerant?
R454B is a lower-GWP A2L refrigerant blend developed primarily for new equipment that historically used R410A-class system architectures. Its lower climate impact does not make it a universal retrofit: the equipment must be designed, listed and installed for R454B and its A2L safety requirements.
R454B refrigerant properties
These values are screening and reference data. Refrigerant-property values can vary slightly by equation of state, assessment report, supplier dataset and regulatory basis. Use the source required by the applicable equipment standard or regulation.
| Property | Reference | Engineering / source note |
|---|---|---|
| Designation | R454B | ASHRAE refrigerant designation |
| Refrigerant type | Zeotropic HFO/HFC blend | R32 + R1234yf |
| Nominal composition | R32 / R1234yf = 68.9 / 31.1 mass % | Supplier technical data |
| Average molecular weight | Approx. 62.6 g/mol | Blend reference value |
| Normal boiling region | Approx. −50.9°C | Use supplier bubble/dew data for design |
| Critical temperature | Approx. 77°C | Supplier technical data |
| Temperature glide | Approx. 1.5 K | Small but non-zero; blend handling still matters |
| ODP | 0 | No ozone depletion |
| 100-year GWP | 465 | U.S. EPA Technology Transitions reference |
| Safety classification | A2L | Lower flammability |
Scientific assessment reports periodically update climate metrics, while regulations may continue using a fixed reference value. This page identifies the regulatory or technical basis for the value shown instead of presenting one number as universal.
R454B composition, glide and charging behavior
Because R454B is a zeotropic blend, engineering work should use the supplier’s bubble-point and dew-point pressure–temperature data rather than treating it exactly like a pure fluid. Its temperature glide is relatively small, but it is still a blend and composition management matters during charging, recovery and leak diagnosis.
R454B should normally be transferred and charged according to the refrigerant supplier and equipment manufacturer instructions. A significant leak can alter the remaining composition under some conditions, so topping off without diagnosing the leak and following approved service procedures should not be assumed acceptable.
Refrigerant choice affects pressure, compressor operation, lubricant, controls, charge, safety classification, component approval and regulatory compliance. Only use a refrigerant in equipment and conversion procedures explicitly approved for it.
Where is R454B used?
Applications depend on equipment design, refrigerant charge, climate, capacity, location and local rules. The examples below describe established or emerging use contexts, not blanket authorization for every system.
Residential & light-commercial AC
New unitary, split and packaged equipment designed and listed for R454B.
Heat pumps
Air-source and reversible heat-pump systems built around A2L refrigerant requirements.
Rooftop & packaged HVAC
Selected commercial platforms where charge, ventilation and mitigation are engineered for R454B.
Positive-displacement chillers
Selected new designs where R454B performance and regulatory fit are appropriate.
For broader research routes, explore the Refrigerant Database, Refrigerant Replacements and Low-GWP Refrigerants guides.
R454B vs R410A
Direct comparisons are useful only when the application, system architecture and regulatory basis are defined. The table highlights major differences rather than implying interchangeability.
| Characteristic | R454B | R410A |
|---|---|---|
| Refrigerant type | R454B: zeotropic blend | R410A: near-azeotropic HFC blend |
| Composition | R32/R1234yf 68.9/31.1 | R32/R125 50/50 |
| EPA 100-year GWP | 465 | 2,088 |
| Safety class | A2L | A1 |
| Temperature glide | Small, about 1.5 K | Very small |
| New-equipment role | Major lower-GWP route | Legacy/high-GWP transition refrigerant |
| Retrofit assumption | No universal drop-in retrofit | Existing R410A equipment remains R410A unless manufacturer-approved conversion exists |
What does A2L mean for R454B?
R454B is classified A2L. The “A” indicates the lower-toxicity group and “2L” indicates lower flammability with limited burning velocity under the classification criteria. A2L equipment may require refrigerant detection, airflow, charge limits, ignition-source controls, labels and service procedures defined by the applicable product standard and code.
Flammability
Do not treat R454B as nonflammable simply because its burning velocity is limited.
Blend behavior
Use R454B-specific service data rather than assuming an R32-only or R1234yf-only response.
Equipment approval
R454B belongs in equipment specifically designed and approved for it.
Actual risk depends on refrigerant charge, release rate, room volume, ventilation, ignition sources, pressure, occupancy, equipment construction, alarm/mitigation logic, service procedure and applicable codes.
See the site-wide Refrigerant Safety Guide for an overview of A1, A2L, A3 and B2L classifications.
R454B refrigerant leak detection
Define the monitoring function first
Fixed detection may be part of an A2L mitigation strategy depending on equipment design, refrigerant charge and occupied-space conditions. A detector should have a validated response to the R454B blend, appropriate range and response time, and compatibility with expected temperature, humidity and airflow. Service sniffers, fixed mitigation sensors and refrigerant identifiers perform different functions.
Regulatory position of R454B in 2026
United States
In the United States, the EPA Technology Transitions program sets a 700-GWP limit for several stationary residential and light-commercial air-conditioning and heat-pump products/systems. R454B’s EPA GWP value of 465 is below that threshold, but SNAP use conditions, equipment standards and local codes still apply.
European Union
In the European Union, Regulation (EU) 2024/573 progressively tightens GWP thresholds for air-conditioning, heat pumps and chillers. R454B is below R410A but above 150, so its long-term fit varies by equipment category, capacity and implementation date.
Always verify the exact equipment category, manufacture/import date, installation date, charge size, safety standard and jurisdiction before making a compliance decision.
Is R454B being phased out?
R454B is not under one universal global ban in 2026. It is a transition refrigerant with substantially lower GWP than R410A, yet future rules in some markets move specific equipment categories toward GWP 150 or lower.
Use the Refrigerant Regulations Hub for country- and region-level research.
What should be compared with R454B?
There is no universal “best” refrigerant. Compare options by system architecture, safety class, GWP basis, expected efficiency, charge, climate, supply chain, serviceability and regulatory lifetime.
R32
Single-component A2L option with EPA GWP 675.
R290
Very-low-GWP A3 hydrocarbon requiring dedicated flammable-refrigerant design.
R744
CO₂ option with GWP 1 and a very different high-pressure system architecture.
Use the Refrigerant Tools hub for additional screening and calculation routes.
R454B refrigerant FAQ
What is R454B refrigerant?
What is the GWP of R454B?
Is R454B flammable?
Can R454B replace R410A directly?
Does R454B have temperature glide?
Is R454B legal in the United States?
Will R454B be a permanent replacement for R410A?
How is an R454B leak detected?
R454B sources and further reading
The page was built from primary regulatory, standards, scientific and manufacturer technical references. Re-check the latest source before equipment design, service or compliance decisions.
Working with R454B or another refrigerant?
Use Refrigerants.net to compare refrigerants, understand safety classifications and research the current transition path for your application.
Technical Notice: This page is for refrigerant research and general technical reference. Refrigerant suitability, permitted charge, equipment approval, leak mitigation, servicing procedures and regulatory compliance depend on the specific equipment, installation and jurisdiction. Always verify current manufacturer documentation, applicable standards, SDS and local regulations before selecting, replacing, charging or servicing a refrigerant.