R452B Refrigerant67/7/26 R32/R125/R1234yf · Opteon XL55 · R410A-class HVAC transition
R452B is a lower-GWP A2L blend developed for air conditioning and heat pumps that historically used R410A-class technology. It contains 67% R32, 7% R125 and 26% R1234yf by mass. Its current EPA GWP of 698 places it just below the 700-GWP limit used for major U.S. residential and light-commercial AC / heat-pump pathways, while its pressure and capacity characteristics were designed to remain relatively close to R410A.
What is R452B refrigerant?
R452B is an A2L zeotropic blend intended mainly for new air-conditioning, heat-pump, chiller and industrial-AC equipment. It should not be treated as a field drop-in for an existing R410A system because the safety class changes from A1 to A2L. Equipment listing, charge limits, ignition-source control, service tooling and mitigation requirements must be designed around the refrigerant.
R452B refrigerant properties
Use these values for research and screening. For equipment design, charging and compliance, use the exact supplier PT data, SDS, OEM documentation and regulation that governs the project.
| Property | Reference | Engineering / source note |
|---|---|---|
| Designation | R452B | ASHRAE designation / Opteon XL55 |
| Nominal composition | R32/R125/R1234yf = 67/7/26 mass % | Published product data / scientific literature |
| Refrigerant type | Zeotropic HFC/HFO blend | Three components |
| Molecular weight | ≈63.5 g/mol | Published R452B data |
| Bubble / boiling point near 1 atm | ≈ −51°C | Supplier data |
| Dew point near 1 atm | ≈ −50.3 to −49.8°C | Supplier data |
| Temperature glide | Small, roughly 0.7–1.2 K depending reference/condition | Use exact PT table |
| Critical temperature | ≈76–77°C | Published property data |
| ODP | 0 | No ozone depletion |
| 100-year GWP | 698 | EPA Technology Transitions |
EPA Technology Transitions uses the values shown on this page. Older product literature may use IPCC AR4/AR5 or another assessment, so a different number is not automatically an error.
Where is R452B used?
Applications must be evaluated by system type, charge, compressor, heat exchanger, safety class and current regulation. The examples below describe recognized use contexts, not automatic approval for every installation.
Residential & light-commercial AC
EPA SNAP lists R452B for new equipment subject to A2L use conditions.
Heat pumps
Designed as an R410A-class lower-GWP option for purpose-built heat-pump systems.
Positive-displacement chillers
EPA lists R452B as acceptable with use conditions in new chillers.
Industrial process air conditioning
EPA lists R452B for new equipment subject to use conditions.
Residential dehumidifiers
EPA SNAP includes R452B in new equipment subject to A2L conditions.
High-ambient HVAC
Its R410A-like pressure/capacity intent makes it relevant to systems designed for demanding ambient conditions.
Continue through the Refrigerant Replacements and Low-GWP Refrigerants hubs for broader selection context.
Why R452B sits unusually close to the U.S. 700-GWP limit
EPA’s current Technology Transitions reference value is 698. That puts R452B only two GWP points below the 700 threshold applied to major residential/light-commercial AC and heat-pump product and system categories.
This means assessment basis matters. Older technical literature can show values such as 676 or 691, while current U.S. compliance should use EPA’s regulatory reference.
A refrigerant can therefore be technically 'below 700' while having very little numerical margin. Compliance decisions should use the current EPA table, not an older brochure.
R452B vs R410A: close thermodynamics, different safety architecture
R452B was formulated to retain R410A-like pressure, capacity and efficiency behavior. That can reduce compressor and heat-exchanger redesign compared with moving to a very different refrigerant family.
The critical difference is safety classification: R410A is A1 while R452B is A2L. Existing R410A equipment was not automatically designed for lower-flammability refrigerant.
New R452B systems therefore need the applicable A2L component approvals, charge controls, service procedures and equipment standard compliance.
Why 7% R125 is in the blend
R452B contains a much smaller R125 fraction than R410A. R125 contributes to finished-blend behavior, including flammability and thermodynamic characteristics, while R32 provides much of the capacity and R1234yf lowers overall GWP.
The formulation is a compromise among GWP, capacity, pressure, efficiency and lower-flammability behavior. No single component determines the finished refrigerant’s complete performance.
That is also why a detector calibrated for pure R32 should not automatically be treated as equivalent to an R452B-calibrated sensor.
R452B is not the same market proposition as R454B
Both are A2L R410A-class alternatives, but R452B is a 67/7/26 three-component blend and R454B is a 68.9/31.1 two-component R32/R1234yf blend.
EPA’s current GWP values are 698 for R452B and 465 for R454B. R454B therefore provides more regulatory margin under a 700 limit.
Equipment manufacturers choose between refrigerants based on compressor/platform strategy, flammability performance, efficiency, charge, supply chain and long-term regulation—not GWP alone.
R452B vs R454B
The table highlights engineering differences rather than implying direct interchangeability.
| Characteristic | R452B | R454B |
|---|---|---|
| Composition | R32/R125/R1234yf = 67/7/26 | R32/R1234yf = 68.9/31.1 |
| EPA GWP | 698 | 465 |
| Safety class | A2L | A2L |
| Temperature glide | Small | Small |
| R125 component | 7% | None |
| Primary role | R410A-class AC / heat pumps | R410A-class AC / heat pumps |
| Margin below U.S. 700 threshold | Very small | Much larger |
R452B safety: R410A-like performance does not mean R410A-like A1 handling
R452B is A2L. Its lower flammability is less severe than A3 hydrocarbons, but it still changes system design and service requirements relative to R410A. Charge, occupied volume, ventilation, ignition sources, service tools and any required refrigerant detection must follow the applicable A2L standard and manufacturer instructions.
A2L equipment design
Use components and systems specifically approved for lower-flammability refrigerant.
Charge / room relationship
Permitted charge can depend on occupancy, room area and mitigation design.
Service tooling
Recovery, vacuum, charging and leak-detection tools must be suitable for A2L refrigerants.
Actual risk depends on charge, release rate, pressure, room volume, ventilation, ignition sources, equipment construction, alarm logic and service condition.
See the Refrigerant Safety Guide for classification context.
R452B refrigerant leak detection
Validate detector response to the finished blend
GasNose includes R452B in its refrigerant detection library. Use NDIR, semiconductor or other sensing technology explicitly validated for the finished R452B blend and the required alarm range. Equipment mitigation sensors and handheld leak sniffers perform different functions and should not be substituted for one another.
Portable service leak detectors, fixed area monitors, A2L mitigation sensors and refrigerant identifiers perform different functions. Define the alarm action and concentration range before selecting the technology.
Regulatory position of R452B in 2026
United States
EPA SNAP lists R452B as acceptable with use conditions in new residential/light-commercial AC and heat pumps, positive-displacement chillers, industrial process air conditioning and other selected end uses. EPA Technology Transitions uses GWP 698, narrowly below the 700 limit that applies to important new residential/light-commercial AC and heat-pump pathways.
European Union
R452B is lower-GWP than R410A but still well above 150. EU Regulation 2024/573 therefore gives it a transitional rather than universally long-term position, especially as later equipment categories move toward lower thresholds or non-fluorinated solutions.
Is R452B being phased out?
R452B can support R410A-class transition where A2L equipment is designed around it, but its GWP is close to 700 and considerably above newer sub-150 solutions. Long-term fit depends strongly on the equipment category and region.
U.S. refrigeration limits differ by cold storage, supermarket, remote condensing, stand-alone product, industrial process and chiller category. A refrigerant may fit one pathway and fail another.
Use the Refrigerant Regulations Hub for regional research.
What should be compared with R452B?
Compare the real equipment pathway: retrofit vs new system, A1 vs A2L capability, GWP threshold, glide, compressor envelope, energy efficiency and service ecosystem.
Practical misconceptions about R452B
“R452B is a drop-in R410A replacement.”
The safety class changes from A1 to A2L; equipment must be designed/approved for R452B.
“R452B GWP is always 676.”
Older AR5-type references can show ~676; current EPA Technology Transitions uses 698.
“Small glide means it is a pure refrigerant.”
R452B is a three-component zeotropic blend.
“If it is below 700, it is future-proof.”
Its regulatory margin is only two points under the current EPA reference and other sectors/regions use lower limits.
R452B refrigerant FAQ
Concise answers to common composition, retrofit, glide, safety and regulation questions.
What is R452B?
What is the EPA GWP of R452B?
Is R452B flammable?
Does R452B have temperature glide?
Can R452B replace R410A directly?
Where is R452B used?
Does R452B meet the U.S. 700-GWP HVAC limit?
Why is R125 included?
Is R452B the same as R454B?
How should R452B leaks be detected?
R452B sources and further reading
This profile uses current EPA regulatory references plus refrigerant supplier, NIST, scientific and GasNose resources. Re-check the latest edition before design or compliance decisions.
Working with R452B or planning a refrigerant transition?
Compare GWP, safety class, temperature glide, equipment compatibility and regulatory lifetime before selecting a refrigerant.
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 exact equipment, installation and jurisdiction. Always verify current manufacturer documentation, SDS, applicable standards and local regulations before selecting, replacing, charging or servicing a refrigerant.