R407A and R407C contain the same three refrigerants in different proportions, and those proportions suit different jobs. R407C is usually the relevant candidate for supported R22 air-conditioning and heat-pump applications. R407A is usually the relevant candidate for supported medium- and low-temperature commercial refrigeration. There is overlap, particularly in medium-temperature refrigeration, so the final letter alone cannot settle a system selection.
The practical question is what each formulation does in the equipment you have. A blend that closely matches an air conditioner's operating conditions may offer a different capacity, pressure relationship, or compressor cooling requirement in a freezer. Neither product is a universal substitute for the other, even when both appear in an R22 replacement search.
This comparison explains the composition, application overlap, temperature glide, and performance evidence behind that distinction. It is intended for owners, purchasing teams, and HVAC/R professionals evaluating an existing specification. For the broader repair-versus-conversion decision, use GetFreon's guide to choosing refrigerant for an older AC system.
R407A vs R407C at a glance
| Characteristic | R407A | R407C |
|---|---|---|
| Main application emphasis | Medium- and low-temperature refrigeration | Air conditioning, heat pumps, and selected refrigeration |
| Composition by mass | 20% R32, 40% R125, 40% R134a | 23% R32, 25% R125, 52% R134a |
| Blend behavior | Zeotropic, with temperature glide | Zeotropic, with temperature glide |
| Lubricant in cited R22 retrofit guidance | Approved POE | Approved POE |
| 100-year GWP, Arkema AR5 basis | 1,923 | 1,624 |
| What determines selection? | Exact equipment approval and performance at the required operating conditions | |
The application, lubricant, composition, and same-basis GWP comparison follows Arkema's R22 retrofit reference. Its application ranges identify direct-expansion equipment. Those ranges are an orientation for evaluation, not permission to convert every system in the category.
Same ingredients, different refrigerant
Both products combine R32, R125, and R134a. The largest percentage difference is R125: R407A contains 40% by mass, while R407C contains 25%. R407C contains more R134a and slightly more R32. These are manufactured formulations, not ingredient lists that a technician can adjust to suit a job.
The letter identifies a distinct blend composition. It does not rank quality, indicate cylinder size, or mean that R407C is an upgraded R407A. A purchase order that specifies only “R407” is incomplete. The full designation matters as much in a pressure-temperature chart or electronic controller as it does on the cylinder.
Changing component proportions changes the blend's thermodynamic behavior. Consequently, matching three ingredient names does not establish matching capacity, vapor density, saturation pressures, or temperature glide. Nor can the suitability of the finished blend be inferred from the suitability of one ingredient. Equipment approved for R134a, for example, is not thereby approved for every blend containing it.
This also explains why mixing R407A and R407C produces neither standard product. Even if both cylinders contain the stated three HFCs, their combined proportions differ from either original product. Published performance data belongs to the specified refrigerant. A field mixture has no basis for borrowing either blend's identity.
For a facility with both products on site, treat them as separate stock items. The similarity of their names is useful for understanding their chemistry, but it is a poor shortcut for assigning refrigerant to equipment.
Why R407C usually leads the AC and heat-pump comparison
Chemours positions R407C for positive-displacement air-conditioning equipment, residential and commercial AC, and heat pumps. It also identifies medium-temperature refrigeration uses. That application history makes R407C the more relevant starting point of these two blends when the load is occupied-space cooling.
Think about the equipment's task. An office rooftop must provide the required cooling through changing weather and occupancy. A heat pump must operate in both its heating and cooling duties. The reason to evaluate R407C is its documented application fit, rather than the mere fact that the old refrigerant was R22.
For a heat pump, a favorable cooling result does not answer the entire question. The comparison also needs the heating operating range, including the conditions in which the outdoor coil serves as the evaporator. A recommendation based only on a summer AC example leaves the winter duty unevaluated. The exact equipment manufacturer's support should cover the intended use.
“Chiller” also needs a qualifier. Arkema's R407C product guidance includes non-flooded evaporator chillers and cautions against flooded-evaporator use because of the blend's glide. Two machines that both produce chilled water can have different refrigerant-side designs. Their shared output does not establish a shared conversion route.
R407A's refrigeration role does not give it an automatic place in an AC proposal. If it is proposed for a particular comfort-cooling system, the useful evidence is approval and performance data for that combination. A broad supplier category such as HVAC/R cannot provide that evidence. Where only R407C has documented support, comparing cylinder prices with R407A creates an alternative that the engineering decision has not established.
Why R407A usually leads the commercial-refrigeration comparison
Chemours identifies R407A with low- and medium-temperature refrigeration, including supported replacement of R22 and conversions of existing R404A refrigeration equipment. This places it in the discussion for cold rooms, refrigerated displays, and freezer systems. It does not mean every appliance in a food business uses or can accept it.
The distinction between medium and low temperature describes the refrigeration duty. It is not determined by the business type. A supermarket can have separate chilled-food and frozen-food circuits with different evaporating conditions. A restaurant may have a walk-in cooler, a freezer, and self-contained appliances that follow entirely different specifications.
A room setpoint is also not an evaporating temperature. Heat must pass from the space or product to the refrigerant, so the relevant comparison includes the temperature difference through the evaporator. Calling a project “a 35-degree cooler” gives the owner a useful description of the goal, but it does not supply the compressor selection point.
For a freezer, the demanding condition may involve low evaporating temperature combined with high condensing temperature. For a cooler, the concern may be maintaining sufficient capacity through normal product loading and changing outdoor conditions. Those are different questions from whether the same compressor can satisfy a comfort-cooling rating point.
R407A's application emphasis makes it a candidate for this analysis. It does not guarantee more capacity or lower electricity use than R407C at every point. If both are permitted, the specific system comparison still decides. If the project includes other alternatives or new equipment, GetFreon's commercial refrigeration selection guide covers that wider decision.
The overlap matters: R407C is not an AC-only refrigerant
The simplest AC-versus-refrigeration distinction becomes misleading when it is treated as an absolute rule. The Chemours R407C FAQ expressly recognizes many medium-temperature systems formerly using R22. Its separate discussion of R502 replacement specifies medium-temperature applications with evaporator temperatures above 20°F, or approximately −6.7°C. That qualification belongs to that stated application; it is not a universal boundary for every R407C compressor.
Low-temperature examples also exist. The legacy Copeland changeover bulletin 95-14 addresses R22-to-R407C conversion across high-, medium-, and low-temperature applications within its scope. It requires Demand Cooling in the extended-medium and low-temperature applications it covers, and includes compressor-design restrictions. Finding R407C on that cover is therefore evidence of a possible application, not approval for an unidentified installed unit.
The newer Copeland Discus bulletin AE4-1287 R10, dated September 2024, refines the picture. It discusses low-temperature R407A and R407C operating envelopes with Demand Cooling and specified circumstances without it, where condensing and return-gas temperatures are closely controlled. This is guidance for the stated Discus applications and protection arrangements, not a general exemption from compressor cooling requirements.
The useful conclusion is specific: R407C can be a legitimate refrigeration refrigerant, including in some documented low-temperature configurations. Whether it is legitimate for a particular freezer depends on the current model, configuration, envelope, and required protections. A historical changeover document and a newer compressor bulletin should be read together at the correct scope.
A real example of why a refrigerant mention is not approval
The English-language Copeland ZS09KAE, ZS11KAE, and ZS13KAE guidelines, AGL_Ref_ST_ZSKAE_EN_Rev00, illustrate a subtle reading trap. This edition uses European regulatory references and covers specified models and bill-of-material configurations. Its general warning about blend glide mentions R407C. However, its qualified-refrigerant table lists R407A, R407F, R448A, R449A, R404A, and R134a; R407C is absent from that table.
A text search for “R407C” finds a real occurrence in this OEM document, but the general mention does not establish approval under this edition. The meaningful evidence is the qualified-refrigerant table and applicable operating envelope for the actual model, suffix, region, and revision. Other regional documents or editions can have different approvals; this example does not establish a universal restriction for the ZS family.
The reverse mistake is also possible. A refrigeration family that lists R407A does not prove that all compressors from the same manufacturer accept it. Family names, model suffixes, and regional documentation can matter. A list copied from another compressor's manual does not become transferable because the machines have similar horsepower.
When evaluating this pair, keep two questions separate: does the documentation recognize the refrigerant, and does it qualify the specific compressor in the intended application? Only the second question helps establish eligibility. It can eliminate an apparent alternative before any performance or purchasing comparison is necessary.
Temperature glide changes what a pressure reading means
R407A and R407C are zeotropic blends. During phase change at a given pressure, their temperature changes rather than remaining at one saturation temperature. That temperature span is called glide. It belongs to the mixture's behavior and should not be confused with the thermostat cycling above and below its setpoint.
There are two saturation endpoints. The bubble point describes saturated liquid, where boiling begins. The dew point describes saturated vapor, where evaporation is complete. Arkema's explanation of liquid and vapor pressure shows why blend charts have separate columns and identifies dew data for superheat and bubble data for subcooling.
| Reference | What it represents | Why it matters in this comparison |
|---|---|---|
| Bubble point | Saturated-liquid endpoint | The reference used for liquid subcooling |
| Dew point | Saturated-vapor endpoint | The reference used for vapor superheat |
| Mean or midpoint convention | A stated representation of phase-change temperature | May be used in heat-exchanger or performance comparisons; the convention must be explicit |
For an owner reading a service report, this means that “evaporating temperature” needs a defined basis. Two reports can use the same number while describing different pressure conditions if one uses dew temperature and the other uses a mean value. Comparing R407A with R407C without that detail can make a paper comparison look more conclusive than it is.
Glide also affects the relationship between refrigerant temperature and the air or fluid moving through a heat exchanger. A coil encounters a changing refrigerant temperature across its two-phase region. Its geometry, airflow arrangement, and operating condition determine how well that temperature profile serves the load. A single glide number does not describe the whole coil.
Danfoss's technical paper on high-glide refrigerants explains the consequences for heat-exchanger behavior, expansion-device control, and moisture removal. Its examples illustrate the physics; they are not an R407A-versus-R407C field trial. The relevant lesson is that a change in temperature profile can affect more than the reported cooling capacity.
That matters differently in the two main applications. In comfort cooling, humidity removal accompanies temperature control. In refrigerated storage, moisture removal can matter to unpackaged goods and coil behavior. The decision cannot be reduced to “less glide is always better.” It needs a supported refrigerant and heat-exchanger combination doing the required job.
What the published performance numbers do, and do not, compare
One common error is to lift R407A and R407C numbers from separate rating examples and rank them as though they were tested against each other. The operating temperature and reference refrigerant must match before such a conclusion is justified.
The Chemours R407C and R407A properties bulletin contains a useful example. Table 2a models R407C against R22 at 45°F evaporation and 110°F condensation, with 15°F superheat and 5°F subcooling. Relative capacity is 1.00 for both, while modeled coefficients of performance are 6.27 for R407C and 6.43 for R22. The stated R407C glide is 8.9°F.
Table 2b instead models R407A against R404A at 20°F and −20°F evaporation, 110°F condensation, and 10°F superheat and subcooling. R407A's relative capacities are 0.89 and 0.86 against R404A's 1.00; its stated glide is approximately 8°F. These examples use different reference fluids and duties. They are not a direct R407A-versus-R407C ranking or universal post-conversion predictions.
The numbers demonstrate why the application split exists in the literature. They do not show that R407C has greater freezer capacity because its AC example reaches 1.00. The denominators are different. Treating the two tables as one league table would erase the very conditions that give their numbers meaning.
Capacity and efficiency answer separate questions
Capacity is the rate at which the modeled system removes heat. Efficiency relates that useful output to the energy input. A refrigerant can meet the required load without being the most efficient eligible option, or show attractive efficiency while failing to provide enough capacity in the retained equipment.
For an existing system, the retained compressor and heat exchangers constrain the result. An unchanged nominal size does not guarantee unchanged delivered capacity. The useful comparison keeps the compressor identity and speed, evaporating and condensing conditions, return-gas assumptions, and subcooling basis visible in both columns.
BITZER's R22 alternative comparison guidance makes the same distinction between a theoretical refrigerant comparison and a calculation for the actual compressor and system configuration. It also discusses how glide can affect evaporator utilization and low-load condenser behavior. Consequently, a favorable full-load point should not be the only point considered in a system that spends much of its time at reduced load.
For this pair, a fair result might be that one approved blend has more capacity margin at the demanding condition, while the other has a different efficiency result over normal operation. A useful recommendation explains that tradeoff. A universal percentage advantage detached from a compressor and operating point cannot do so.
Discharge temperature is an application limit, not a quality score
Lower refrigerant temperature in the evaporator does not mean the compressor discharge is cooler. The compressor must raise vapor pressure and temperature to reject heat at the condenser. Its operating limits therefore matter alongside the room or product temperature the system is trying to maintain.
Copeland's Discus guidance explains that R407A and R407C require attention to discharge-temperature control in the described low-temperature applications. It identifies higher discharge temperatures than R404A and lower ones than R22 for the refrigerants discussed. This is why “R407A is used in freezers” cannot be shortened to “R407A needs no additional compressor cooling.” The application envelope contains the conditions.
The same reasoning prevents an overly broad rejection of R407C. A documented low-temperature R407C configuration may include protections and operating constraints that make it viable. Comparing it with an R407A proposal that assumes different return-gas conditions would not isolate the refrigerant difference.
A technically complete pair comparison identifies whether either option depends on additional cooling provisions or a narrower operating range. That is a material difference even when both options provide adequate capacity at one rating point. It affects how much of the intended duty the system can perform within its approved limits.
POE oil is a shared requirement, not the deciding difference
For the R22 retrofit paths cited here, both blends require the appropriate manufacturer-approved polyolester lubricant, or POE. R407C is not the “oil-change version” of an otherwise mineral-oil-compatible R407A. Choosing between the two does not remove the need to establish the actual lubricant and the approved conversion requirements.
The BITZER lubricant guidance for A1 refrigerants shows why the lubricant specification remains tied to the compressor application. “Uses POE” identifies a lubricant family, not every acceptable product or viscosity. A system already converted to one R407 blend does not gain approval for the other merely because POE is present.
Detailed oil-change, recovery, evacuation, and charging procedures belong to the applicable manufacturer instructions and qualified service personnel. They are part of implementing an approved selection, rather than evidence that two refrigerants have become interchangeable.
R407C has the lower GWP here, but that is only one comparison
On the same 100-year AR5 basis used in the opening table, R407C's GWP is lower than R407A's. The distinction is meaningful when comparing equal masses emitted on that basis. It does not determine which blend is approved for a cooler, freezer, air conditioner, or heat pump.
Be careful when collecting figures from different documents. Some sources use an earlier IPCC assessment basis, and the resulting published values differ. A comparison should identify the time horizon and assessment basis for both products. Changing the accounting basis does not change what is inside the cylinder.
It also helps to define the question. GWP compares the warming impact of refrigerant emissions. A system's environmental result additionally depends on the quantity released, recovery, energy consumption, and operating life. The lower GWP of R407C does not prove that converting an R407A installation to it improves the complete system's performance or lifetime impact.
For current project eligibility, use the applicable requirements rather than a generic “lower-GWP” label. The EPA's Technology Transitions sector guidance organizes restrictions by equipment category and activity. A refrigerant's suitability for servicing an existing installation and its eligibility in a newly installed system are separate questions. This article does not treat either R407 blend as a universal new-equipment recommendation.
If the project has expanded into a broader commercial-refrigeration strategy, the GetFreon commercial refrigerant overview provides context for other products encountered in the same service market. Keep that wider comparison separate from deciding whether an existing circuit specifically calls for R407A or R407C.
Three situations where the distinction changes the answer
An office rooftop with a supported R407C conversion
The technical evaluation names R407C, but purchasing receives an R407A quote in the same package size. There is no demonstrated alternative yet. The task is to obtain the specified product or return the proposed change to the technical decision-maker. Matching pounds and similar lettering do not preserve the approved refrigerant specification.
This remains true even if the R407A quote is cheaper. A cost comparison becomes relevant only after both options have a supported application. Otherwise, the apparent saving belongs to a different product with an unresolved use case.
A freezer with a documented R407C compressor application
A general article says R407A is associated with low-temperature refrigeration, while the contractor presents a model-specific R407C application. The correct response is to examine that documentation and its conditions. The ordinary product positioning does not invalidate a supported exception.
The important distinction is between a complete configuration and a refrigerant name on a brochure. The selected envelope, discharge-temperature provisions, and installed compressor details must explain why this freezer falls within the documented application. The example should remain an exception with evidence, not become a new blanket recommendation.
A medium-temperature installation eligible for both blends
This is a genuine R407A-versus-R407C engineering comparison. The evaluation can consider capacity margin, efficiency, glide effects in the retained coils, and the compressor operating range under the same assumptions. The more suitable result may depend on the busiest operating condition or on how the system behaves at reduced load.
Here, purchasing can compare the approved supply options after the technical decision has been defined. If changing blends would require a new conversion scope, that scope belongs in the decision. An existing R407A charge and an existing R407C charge are never interchangeable inventory simply because both options were once considered.
Order the exact blend the system specification names
First distinguish a service purchase from a new selection. A freezer already operating on a documented R407C conversion does not become an R407A system because a general comparison associates R407A with refrigeration. Likewise, an approved R407A cooler does not become a candidate for an unplanned switch simply because R407C has a lower GWP. The established circuit specification remains the starting point for its service supply.
For equipment originally labeled R22, use the latest conversion records as well as the original nameplate. A clear record should resolve which blend the system now uses. An unclear record is a refrigerant-identification problem for the service professional, rather than a reason for the buyer to choose whichever R407 cylinder is easier to obtain.
GetFreon has separate listings for a 25 lb R407A refrigerant cylinder and a 25 lb R407C refrigerant cylinder. Use the listing that matches the approved system or conversion specification. Package weight is a purchasing quantity; it does not establish a system's required refrigerant charge.
Keep the full designation consistent from the technical recommendation to the order and receiving check. For a mixed site, identify the equipment or circuit as well as the refrigerant. “For the store” is ambiguous when the store has both comfort-cooling and refrigeration systems.
Current price, stock, and delivery terms belong to the live product listing and order details. None of those commercial factors changes the refrigerant's approved application. If the requested designation is unavailable, the substitution decision needs its own technical basis before the order changes.
Frequently asked questions
Are R407A and R407C interchangeable?
No. Their component refrigerants are the same, but their proportions and properties differ. Use the exact refrigerant specified for the equipment or an approved conversion. Neither their shared number nor their shared lubricant family establishes interchangeability.
Which is normally considered for an R22 air conditioner?
R407C is normally the more relevant candidate of this pair for a supported comfort-cooling application. A specific R407A proposal would need its own equipment and compressor support. Neither option is approved by the original R22 label alone.
Can R407C be used in a freezer?
Some compressor documentation supports low-temperature R407C applications under defined conditions. That does not make it suitable for every freezer. Use the current documentation for the exact compressor, system configuration, operating range, and required protection or cooling provisions.
Does R407A always have more refrigeration capacity?
No universal ranking follows from the designation. Capacity depends on the compressor, system, and rating conditions. Compare both eligible blends at equivalent conditions rather than comparing an R407A freezer example with an R407C air-conditioning example.
Can the same pressure-temperature chart be used for both?
No. Select the exact refrigerant and the appropriate bubble or dew reference for the measurement. A chart or controller setting that says R407C should not be used as though it says R407A.
Does a lower GWP make R407C the better replacement?
Only if the rest of the selection supports it. GWP is one environmental comparison, while equipment eligibility, required capacity, operating limits, energy use, and applicable project restrictions remain separate considerations.
Can one blend be added to a system containing the other?
No. Adding R407A to R407C, or the reverse, changes the specified formulation. A supported refrigerant change is a documented conversion decision. It is not permission to combine products during service.
The selection rule: begin with the application, preserve the exact refrigerant identity, and use model-specific evidence wherever the two blends overlap. R407C's AC and heat-pump role and R407A's refrigeration role are useful starting points. The approved operating range and a fair performance comparison determine whether either belongs in the actual system.
Technical sources reviewed October 1, 2026. Linked manufacturer documents have different scopes and revision dates; current instructions for the actual equipment govern its selection and service.
