R22 and R407C are two refrigerants often compared in the HVAC industry, especially when homeowners, contractors, or service technicians are evaluating options for older air conditioning systems.
Because many older residential and commercial HVAC systems were originally designed for R22, people often search for alternatives when repair costs rise or R22 availability becomes limited. R407C is one refrigerant that frequently appears in those discussions.
However, it is important to understand that R407C is not a simple drop-in replacement for R22. Refrigerant compatibility affects system performance, compressor reliability, lubrication, operating pressure, charging procedures, and long-term maintenance.
If your system requires refrigerant, you can view available options here:
Buy R22 Refrigerant
View R407C Refrigerant
What Is R22?
R22, also known as HCFC-22, was one of the most widely used refrigerants in residential and commercial air conditioning systems for decades.
It became popular because of its reliable cooling performance, stable operating characteristics, and broad compatibility with older HVAC equipment.
R22 was commonly used in:
Residential central air conditioners
Heat pumps
Commercial rooftop HVAC units
Older refrigeration systems
Although the production and import of new R22 ended in the United States in 2020, existing R22 systems can still continue operating. According to EPA phaseout guidance, after 2020, only recovered, recycled, or reclaimed R22 supplies are available for servicing existing systems.
This means R22 equipment is not automatically illegal to use, but servicing these systems may become more expensive over time.
What Is R407C?
R407C is an HFC refrigerant blend commonly used in air conditioning and certain refrigeration applications.
It was developed as one of the alternatives to ozone-depleting refrigerants such as R22. Unlike R22, R407C does not contain chlorine and has zero ozone depletion potential.
R407C is commonly associated with:
Residential air conditioning
Commercial HVAC systems
Water chillers
Certain retrofit applications
Some medium-temperature refrigeration systems
However, R407C is a blended refrigerant, not a single-component refrigerant. This means it has different handling requirements compared with R22.
Why Do People Compare R22 and R407C?
People often compare R22 and R407C for three main reasons.
1. Many Older Systems Still Use R22
A large number of HVAC systems installed before the R22 phaseout still operate today. When these systems need service, owners often look for refrigerant options that may help extend equipment life.
2. R22 Supply Is More Limited
Since new R22 production and import ended in the U.S., available supply mainly comes from recovered, recycled, or reclaimed refrigerant. This can affect price and availability.
3. R407C Has Similar Applications
Compared with some newer refrigerants, R407C has operating characteristics that are closer to R22 in certain applications. This is why it is often discussed as a possible retrofit option.
However, “similar” does not mean “identical.”
Is R407C a Direct Replacement for R22?
No. R407C should not be treated as a direct drop-in replacement for R22.
Some R22 systems may be retrofitted to use R407C, but this usually requires professional evaluation and system modifications. The exact requirements depend on the equipment design, compressor type, oil type, system condition, and manufacturer recommendations.
A proper retrofit may involve:
Recovering the existing R22
Checking for leaks
Replacing or changing the lubricant
Using POE oil where required
Replacing the filter drier
Inspecting seals and gaskets
Evacuating the system properly
Charging R407C correctly
Adjusting the expansion device if needed
Testing superheat, subcooling, and system performance
Relabeling the system after retrofit
R407C generally requires POE lubricant. Many older R22 systems use mineral oil or alkylbenzene oil, which may not provide proper oil return with R407C. Manufacturer retrofit guidance commonly notes that oil compatibility is a critical part of the conversion process.
For this reason, R407C should only be used in an R22 system after a qualified HVAC technician confirms compatibility.
Pressure Differences Between R22 and R407C
R407C is often discussed as an R22 retrofit option because its pressure-temperature characteristics are closer to R22 than some other refrigerants.
However, the two refrigerants are not identical.
Important differences include:
Operating pressure
Temperature glide
Oil compatibility
Charging method
Expansion valve behavior
System capacity and efficiency
Compressor lubrication
Even small differences can affect cooling performance and compressor reliability. A system that runs acceptably on R22 may not perform the same way after being converted to R407C without proper adjustments.
R407C Has Temperature Glide
One major difference between R22 and R407C is temperature glide.
R22 is a single-component refrigerant, while R407C is a zeotropic blend. This means R407C evaporates and condenses over a range of temperatures rather than at one fixed temperature.
Temperature glide matters because it affects:
Charging procedures
System diagnostics
Superheat readings
Subcooling readings
Leak behavior
Refrigerant composition over time
Because of this, technicians need to use the correct pressure-temperature chart and follow the proper charging method when working with R407C.
How Should R407C Be Charged?
R407C should generally be charged as a liquid, not as vapor.
Because it is a blended refrigerant, vapor charging may change the refrigerant composition and affect system performance. Professional charging procedures should be followed carefully to avoid compressor damage or incorrect system operation.
The system should also be properly evacuated, leak-tested, and charged by weight according to manufacturer guidance.
Can You Mix R22 and R407C?
No. R22 and R407C should never be mixed.
Mixing refrigerants can cause serious problems, including:
Unstable operating pressures
Reduced cooling performance
Compressor damage
Oil return problems
Contaminated recovery cylinders
Difficult or impossible refrigerant reclamation
Service complications
If a system is being converted from R22 to R407C, the existing R22 should be properly recovered first. The system should then be serviced according to approved retrofit procedures.
Why Some Owners Continue Using R22
Although R407C retrofit discussions are common, many owners continue using R22 systems when the equipment is still in good condition.
Common reasons include:
The system still cools effectively
The compressor is still working properly
Repair costs are still manageable
Full system replacement is expensive
The equipment may still have usable service life remaining
In many cases, continuing to service an R22 system may be practical if the system is not leaking heavily and the main components are still reliable.
You can check current product availability here:
R22 Refrigerant for Sale
When Might an R407C Retrofit Be Considered?
An R407C retrofit may be considered when:
The system is still mechanically sound
The compressor is in good condition
The owner wants to delay full replacement
R22 service costs are becoming too high
The system has been inspected by a qualified technician
The equipment manufacturer allows or supports the retrofit
However, a retrofit is not always the best solution. If the system is very old, inefficient, leaking frequently, or has major component failure, replacement may be more cost-effective.
Is It Better to Retrofit or Replace the System?
There is no universal answer. The better choice depends on the system and the owner’s budget.
System Age
Older systems may already be near the end of their service life. In that case, investing in a retrofit may not be worthwhile.Compressor Condition
If the compressor is weak, noisy, overheating, or near failure, changing refrigerant will not solve the underlying problem.
Leak History
A system with repeated leaks may continue to lose refrigerant even after a retrofit.
Energy Efficiency
Newer HVAC systems may offer better efficiency, lower operating costs, and improved humidity control compared with aging R22 equipment.
Repair Cost vs Replacement Cost
If the repair cost is high, replacement may provide better long-term value.
Common Mistakes to Avoid
Assuming R407C Is a Drop-In Replacement
R407C is not a simple drop-in replacement for R22. Professional evaluation is required.
Ignoring Oil Compatibility
Oil compatibility is one of the most important parts of an R22 to R407C retrofit. R407C commonly requires POE oil, while many R22 systems use mineral oil or alkylbenzene oil.
Charging the Refrigerant Incorrectly
Because R407C is a blend, it should generally be charged as a liquid and by weight.
Mixing Refrigerants
Never mix R22 and R407C in the same system.
Skipping System Labeling
After a retrofit, the system should be clearly labeled with the new refrigerant type, lubricant type, and charge amount.
Ignoring Manufacturer Guidelines
Always check the equipment manufacturer’s recommendations before converting a system.
R22 vs R407C: Quick Comparison
| Feature | R22 | R407C |
|---|---|---|
| Refrigerant type | HCFC | HFC blend |
| Contains chlorine | Yes | No |
| Ozone depletion potential | Yes | Zero ODP |
| Common use | Older AC and refrigeration systems | AC, chillers, selected retrofit applications |
| Oil type | Often mineral oil or alkylbenzene | Usually POE oil |
| Drop-in replacement? | Original refrigerant for many older systems | No |
| Temperature glide | No significant glide | Yes |
| Charging method | Standard refrigerant procedures | Usually liquid charging required |
| U.S. new production/import | Ended in 2020 | Still used, subject to HFC regulations |
Related Articles
Complete R22 Refrigerant Guide
R22 Replacement Options
R22 vs R410A
Can You Still Buy R22?
R407C Refrigerant Guide
How to Choose the Right Refrigerant for Older HVAC Systems
Final Thoughts
R407C is commonly discussed as a possible alternative for certain R22 systems, but it should never be treated as a universal or simple replacement.
The most important points to remember are:
R407C is not a direct drop-in replacement for R22.
R22 and R407C should never be mixed.
Oil compatibility must be checked carefully.
R407C has temperature glide and special charging requirements.
A qualified HVAC technician should evaluate the system before any retrofit.
For some older systems, continuing to use reclaimed or recycled R22 may make sense. For others, a professionally planned retrofit or full system replacement may be the better long-term choice.
Before changing refrigerants, always verify equipment compatibility, follow manufacturer guidelines, and work with a qualified HVAC professional.
