What Is the Composition of R-407A?

R407A is a three-component zeotropic HFC refrigerant blend made from R32, R125, and R134A. Its nominal composition by mass is 20% R32, 40% R125, and 40% R134A. Arkema and Chemours both publish this formulation in their technical documentation for R407A.

That exact ratio matters. The blend composition determines the refrigerant’s pressure-temperature relationship, temperature glide, capacity characteristics, discharge behavior, GWP, charging procedure, and suitability for specific applications. R407A is not simply “a mix of common HFCs.” It is a standardized refrigerant with a defined formulation.

The Exact R407A Blend Ratio

What is the composition of R-407A? The nominal blend is 20% R32, 40% R125, and 40% R134A by weight. Refrigerant suppliers and manufacturers specify allowable tolerances around those nominal percentages so the product performs consistently.

R32 Makes Up 20% of R407A

R32 is difluoromethane. Within R407A, it contributes to refrigeration capacity and pressure characteristics. R32 by itself is an A2L refrigerant, but in the R407A formulation the complete blend is classified A1 under the standard refrigerant safety classification.

The presence of R32 is one reason the blend behaves differently from refrigerants that contain more R134A or less R32.

R125 Makes Up 40% of R407A

R125 is pentafluoroethane. It makes up the largest single share alongside R134A. R125 affects the blend’s pressure, capacity, discharge characteristics, and flammability behavior.

R125 also carries a relatively high GWP compared with R32 and R134A, which contributes significantly to the overall GWP of R407A.

R134A Makes Up 40% of R407A

R134A is 1,1,1,2-tetrafluoroethane. It helps shape the blend’s pressure-temperature curve and operating characteristics. R134A is also widely used on its own in automotive, refrigeration, and other applications, but its behavior inside R407A is part of a blend rather than a stand-alone refrigerant.

A technician should never assume that knowing the properties of R134A alone is enough to predict R407A behavior.

Why Those Three Components Are Blended Together

The formulation is designed to produce a set of properties useful in refrigeration and selected retrofit applications. The three components do not contribute identical characteristics, so changing the ratio changes the refrigerant designation and performance.

The Blend Balances Capacity, Pressure, and Operating Range

R32 tends to support capacity, R125 influences pressure and safety behavior, and R134A moderates the blend’s thermodynamic characteristics. The resulting R407A profile can be suitable for medium- and low-temperature refrigeration and certain approved conversions.

Manufacturers developed the blend to provide useful performance in applications historically served by refrigerants such as R22, R404A, or R507A, depending on the equipment and retrofit plan.

The Formula Is Different From R407C

R407C contains the same three components but in a different ratio: 23% R32, 25% R125, and 52% R134A. That is why R407A and R407C should never be treated as interchangeable.

The Chemours Freon 407C and 407A technical bulletin lists both formulations side by side and makes the distinction clear.

R407A Is a Zeotropic Refrigerant Blend

The word “zeotropic” is central to understanding R407A composition. It means the components do not boil and condense at exactly the same temperature during a phase change.

Temperature Glide Is a Direct Result of the Blend

Because the three components have different boiling characteristics, the saturation temperature changes as R407A evaporates or condenses. This change is called temperature glide.

Technicians should use the correct dew-point and bubble-point values during service. Dew temperature is generally relevant to superheat calculations, while bubble temperature is generally used for subcooling.

Blend Composition Can Shift if R407A Is Handled Incorrectly

If a zeotropic blend is withdrawn from a cylinder as vapor, the more volatile components can leave at a different rate than the less volatile components. This process can change the composition of the remaining refrigerant.

For that reason, manufacturers typically instruct technicians to charge R407A as liquid. When liquid must be introduced on the suction side, it should be metered carefully to avoid compressor damage.

Composition Also Explains Why R407A Cannot Be Mixed With Other Refrigerants

Mixing R407A with R407C, R404A, R22, R507A, or another refrigerant creates a composition that no standard pressure-temperature chart represents.

Mixed Refrigerants Produce Unreliable Diagnostic Data

Once refrigerants are mixed, saturation pressures, glide, capacity, and oil return may no longer match either original product. A technician can no longer confidently use the standard R407A pressure-temperature chart.

The system may still appear to cool, but that does not mean it is operating safely or efficiently.

Cross-Contamination Creates Recovery and Reclamation Problems

Mixed refrigerant also complicates recovery. Recovery cylinders should be labeled clearly, and unknown or contaminated refrigerant should be isolated rather than added to clean recovered product.

Good refrigerant identification protects service equipment and reduces the risk of contaminating other customer systems.

R407A Composition and Lubricant Requirements

R407A is an HFC blend, and lubricant compatibility matters during both new-system service and retrofit work.

POE Is Commonly Used With R407A

The Arkema Forane R407A specification notes that POE lubricants should be used because R407A is not sufficiently miscible with traditional mineral or alkylbenzene oils for many applications.

However, the correct POE viscosity and brand approval depend on the compressor. A technician should use the compressor manufacturer’s lubricant guidance rather than a generic “POE is POE” assumption.

Moisture Control Is Especially Important With POE

POE oil is hygroscopic, meaning it absorbs moisture readily. Moisture can contribute to acid formation, oil degradation, and reliability problems.

Keep oil containers sealed, minimize the time the circuit is open, replace driers when required, and evacuate the system to the manufacturer’s specified vacuum before charging.

R407A Composition and Its Environmental Profile

The component mix also determines the refrigerant’s climate impact. GWP values vary depending on the reference assessment, so the source should always be identified.

R407A Has a Higher GWP Than R407C

EPA’s AR4-based values list R407A at approximately 2,107, while R407C is approximately 1,774. EPA’s AR5 equivalency data gives R407A about 1,923 and R407C about 1,624.

The important point is that R407A is a relatively high-GWP HFC blend by current standards, even though it can still play a role in servicing existing equipment.

New Equipment Rules May Limit Where High-GWP HFCs Fit

EPA Technology Transitions rules set increasingly strict GWP limits for many new refrigeration and air-conditioning subsectors. The limit and compliance date depend on the equipment category.

This means R407A can remain relevant to existing-system service and approved retrofit work while not being the preferred refrigerant platform for new equipment in many applications.

Where R407A Is Commonly Used

The composition was developed for practical refrigeration performance, but system approval always comes first.

Medium- and Low-Temperature Refrigeration

R407A is commonly associated with commercial refrigeration, including supermarket, cold-storage, food-processing, and other medium- and low-temperature applications where the equipment is designed or approved for it.

Selected Retrofit Applications

R407A can appear in approved retrofit procedures involving R22, R404A, or R507A equipment, depending on the system design and compressor approval.

A retrofit may require lubricant changes, valve adjustments, different charge quantity, control changes, or updated operating targets. No refrigerant should be described as universally “drop-in” for every legacy system.

How Manufacturers Verify R407A Composition

Professional refrigerant is manufactured and tested to composition and purity specifications. Buyers should be able to identify the manufacturer or packager and obtain product documentation.

Composition Tolerances Matter

Arkema’s R407A customer specification lists nominal concentrations with tolerances around each component. Those tolerances help ensure that the product remains within the defined refrigerant specification.

A cylinder with uncertain source, broken seals, or no documentation is a higher risk because the buyer cannot easily confirm whether the blend is actually within specification.

AHRI 700 Provides a Purity Framework

AHRI Standard 700 establishes purity specifications and test methods for refrigerants. It addresses composition, moisture, non-condensables, high-boiling residue, acidity, and other contaminants.

For contractors, purity documentation matters because even a correctly labeled refrigerant can cause service problems if the product is contaminated or off-specification.

What the Composition Means During Field Service

Knowing the percentages is useful, but the real value is understanding how those percentages change service practice.

Use the Correct R407A Pressure-Temperature Data

Do not substitute R407C, R404A, or R22 pressure charts. The composition determines the saturation relationship, so each refrigerant requires its own data.

Digital manifolds simplify this, but technicians should confirm the selected refrigerant before trusting the displayed dew or bubble temperature.

Charge by Weight and Verify Performance

After repairs or a full evacuation, charge the system according to the equipment or retrofit procedure, then verify superheat, subcooling, compressor amps, discharge temperature, and system capacity.

A correct refrigerant label is only the starting point. Final operating conditions determine whether the system has been commissioned properly.

Frequently Asked Questions

These answers summarize the most common questions about R407A composition.

What Is the Composition of R-407A?

R407A is nominally 20% R32, 40% R125, and 40% R134A by mass.

Is R407A a Pure Refrigerant?

No. It is a three-component zeotropic HFC blend.

Is R407A the Same as R407C?

No. R407C is 23% R32, 25% R125, and 52% R134A, so its properties and applications differ.

Is R407A Flammable?

R407A is classified A1 under standard refrigerant safety classifications, meaning lower toxicity and no flame propagation under the applicable test conditions.

Should R407A Be Charged as Liquid?

Yes. Because it is a zeotropic blend, manufacturers generally instruct technicians to withdraw and charge R407A as liquid to preserve composition.

What Oil Is Used With R407A?

POE lubricant is commonly required, but the exact oil type and viscosity should match the compressor manufacturer’s specification.

Can R407A Be Mixed With R22 or R407C?

No. Mixing refrigerants creates an undefined blend and can cause diagnostic, performance, and recovery problems.

Conclusion: Composition Is More Than a Specification Number

The 20/40/40 ratio of R32, R125, and R134A is what makes R407A behave like R407A. That composition explains its temperature glide, liquid-charging requirement, pressure-temperature curve, lubricant considerations, GWP, and application range.

If your equipment or approved retrofit procedure calls for R407A and you need help confirming cylinder availability, ordering requirements, or current stock, contact Royal Refrigerants with the equipment type and quantity you need.