R471A RefrigerantSolstice N71 · Sub-150 A1 blend · Medium-temperature commercial refrigeration
R471A is an unusual low-GWP refrigerant because it combines an EPA GWP of 144 with an A1 safety classification. It contains 78.7% R1234ze(E), 4.3% R227ea and 17% R1336mzz(E) by mass. Honeywell developed it primarily for medium-temperature commercial refrigeration as a nonflammable alternative in applications where A2L adoption is difficult.
What is R471A refrigerant?
R471A is a three-component A1 blend designed to push commercial refrigeration below the 150-GWP threshold without introducing A2L flammability. EPA lists R471A as acceptable in new equipment across several commercial/industrial refrigeration categories and, since December 2024, also in retrofit equipment for selected cold-storage, supermarket, remote-condensing, food-processing and industrial-process applications.
R471A 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 | R471A | ASHRAE designation / Honeywell Solstice N71 |
| Nominal composition | R1234ze(E)/R227ea/R1336mzz(E) = 78.7/4.3/17 mass % | Honeywell N71 data |
| Refrigerant type | Zeotropic HFO/HFC blend | Three components |
| ODP | 0 | EPA SNAP |
| 100-year GWP | 144 | EPA Technology Transitions |
| Older Honeywell GWP | ≈148 / 146 depending assessment material | Different assessment basis |
| Safety classification | A1 | No flame propagation under classification test |
| Evaporator glide example | ≈4.4°F (~2.4 K) in Honeywell comparison | Operating condition dependent |
| Pressure level | Substantially lower than R404A in Honeywell comparison example | Important equipment-design difference |
| Primary focus | Medium-temperature commercial refrigeration | New equipment and selected retrofits |
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 R471A 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.
Supermarket medium-temperature systems
EPA lists R471A as acceptable; 2024 determination also added retrofit use.
Remote condensing units
Acceptable in new and retrofit equipment under current SNAP listings.
Cold-storage warehouses
EPA lists new equipment and, since 2024, retrofit equipment.
Refrigerated food processing / dispensing
Acceptable in new and retrofit equipment.
Industrial process refrigeration
EPA lists both new and retrofit uses.
Stand-alone equipment
EPA Notice 38 listed R471A in new stand-alone refrigeration equipment.
Continue through the Refrigerant Replacements and Low-GWP Refrigerants hubs for broader selection context.
Why R471A is unusual: A1 and still below GWP 150
Most very-low-GWP fluorinated commercial-refrigeration options achieve sub-150 GWP by accepting A2L flammability. R471A takes a different formulation route and remains A1.
The blend uses a large R1234ze(E) fraction, plus R1336mzz(E) and a small amount of high-GWP R227ea. The finished weighted GWP is still 144 under the current EPA calculation.
This makes R471A especially interesting in sites, jurisdictions or equipment designs where nonflammability is highly valued.
Sub-150 does not mean R471A behaves like R404A
Honeywell’s published N71 comparison shows much lower suction and discharge pressure than R404A under the example medium-temperature cycle, even while reporting favorable efficiency.
That means capacity, compressor displacement, valves and heat-exchanger design can differ significantly from a conventional R404A rack.
R471A should therefore be evaluated as its own refrigerant platform, not as a 'same-pressure sub-150 R404A.'
EPA expanded R471A from new equipment into selected retrofits in 2024
EPA Notice 38 listed R471A in new equipment for industrial process refrigeration, cold storage, stand-alone equipment, refrigerated food processing, remote condensing and supermarket systems.
Acceptability Determination 39, effective December 11, 2024, added retrofit equipment for cold storage, industrial process refrigeration, food processing/dispensing, remote condensing and supermarket systems.
An EPA retrofit listing establishes environmental acceptability under SNAP; it does not replace OEM engineering approval for the specific compressor and system.
Why the 4.3% R227ea fraction matters despite the low finished GWP
R227ea has a relatively high individual GWP, but it is only 4.3% by mass. The weighted blend still reaches EPA GWP 144 because most of the refrigerant consists of much lower-GWP HFO components.
The small R227ea fraction helps the finished blend achieve A1 behavior and the desired thermodynamic characteristics.
This demonstrates why finished-blend properties should be evaluated directly rather than judging a mixture from one component.
R471A vs R515B
The table highlights engineering differences rather than implying direct interchangeability.
| Characteristic | R471A | R515B |
|---|---|---|
| EPA GWP | 144 | 287 |
| Safety class | A1 | A1 |
| Composition | 3 components | 2 components |
| Glide | Moderate/small effective glide | Zero / azeotropic |
| Primary role | Medium-temp commercial refrigeration | Chillers / heat pumps / R134a-class duty |
| Sub-150 | Yes | No |
| Retrofit SNAP listings | Selected categories | Primarily new-equipment listings |
R471A safety: A1 reduces flammability constraints, not all refrigeration hazards
R471A is A1. That can simplify site acceptance compared with A2L sub-150 blends, but large releases can still displace oxygen, liquid refrigerant can cause frostbite and hot work can create decomposition products. Zeotropic charging and composition management also remain relevant.
A1 advantage
No flame propagation under the classification test can simplify some equipment/site strategies.
Low-pressure behavior
Equipment must be designed for the actual R471A pressure/capacity map.
Blend integrity
Use R471A-specific PT, charging and leak-analysis procedures.
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.
R471A refrigerant leak detection
Validate detector response to the finished blend
R471A is not currently one of the dedicated GasNose public refrigerant profile pages. Use fixed or portable detection validated for the finished R471A blend rather than assuming response to R1234ze(E), R227ea or R1336mzz(E) alone. Area-monitoring needs and service leak finding are separate functions.
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 R471A in 2026
United States
EPA lists R471A as A1 with GWP 144 in current SNAP tables. Notice 38 added it for new commercial/industrial refrigeration equipment, and Acceptability Determination 39 added selected retrofit categories effective December 11, 2024. Its GWP is below the 150 thresholds used in many long-term retail-food/cold-storage restrictions, but equipment-specific Technology Transitions and SNAP requirements still apply.
European Union
R471A’s sub-150 GWP and A1 classification can make it attractive under near-term EU F-gas thresholds, although it remains a fluorinated blend and later application-specific restrictions may still favor non-fluorinated systems.
Is R471A being phased out?
R471A is not a high-GWP transition gas in the same sense as R448A/R449A. It is positioned as a low-GWP A1 option, but long-term adoption will depend on compressor/platform availability, cost, efficiency, and future fluorinated-chemical regulation.
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 R471A?
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 R471A
“A1 + GWP 144 means R471A is a drop-in R404A.”
Its pressure/capacity behavior differs substantially; SNAP retrofit listing does not equal universal OEM compatibility.
“R471A is mostly R227ea.”
R227ea is only 4.3%; most of the blend is R1234ze(E).
“R471A has zero glide because it is A1.”
Safety class does not define phase behavior; R471A is zeotropic.
“Below 150 means all future regulation disappears.”
Equipment-specific and future fluorinated-gas restrictions still apply.
R471A refrigerant FAQ
Concise answers to common composition, retrofit, glide, safety and regulation questions.
What is R471A?
What is the EPA GWP of R471A?
What is the composition?
Is R471A flammable?
Does R471A have glide?
Can R471A replace R404A?
Is R471A below GWP 150?
Where is R471A used?
Why is R471A pressure different from R404A?
How should R471A leaks be detected?
R471A 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 R471A 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.