Refrigerant gas R407C has been a reliable choice for air conditioning and heat pump systems, especially since the phase-out of R22. It’s known for being a high efficiency refrigerant and a more eco-friendly alternative. But a common question arises:
Can R407C be used with or mixed with other refrigerants?
Let’s explore what makes R407C refrigerant unique—and why compatibility matters more than you might think.
What Is R407C?
R407C is a zeotropic HFC blend made up of:
R32 (23%)
R125 (25%)
R134a (52%)
This combination gives refrigerant gas R407C a good balance of cooling performance, energy efficiency, and environmental safety (no ozone depletion). It’s commonly used in residential and commercial systems, and it's often considered a go-to R22 replacement.
Since it's chlorine-free, eco-friendly refrigerant R407C meets global environmental regulations like the Montreal Protocol.
Is R407C Compatible With Other Refrigerants?
The short answer: No. Don’t mix refrigerants.
Even though some refrigerants may appear similar, R407C refrigerant is not compatible with:
R22 (its predecessor)
R410A
R134a
Or any other refrigerant
Here’s why:
R407C is a zeotropic blend, which means it has a glide—its components boil at different temperatures. Mixing it with another refrigerant changes the pressure-temperature relationship and disrupts system performance.
Mixed refrigerants can lead to:
Inaccurate superheat/subcooling readings
Reduced efficiency and cooling capacity
Compressor overheating or failure
Loss of manufacturer warranty
In many countries, it's illegal to mix refrigerants due to safety and environmental risks.
What If I’m Replacing R22?
You can use R407C refrigerant for R22 system retrofits, but the process must be done correctly.
Key retrofit steps:
Recover all R22 (don’t mix)
Flush or replace components if needed
Switch from mineral oil to POE oil
Check for material compatibility (especially seals and O-rings)
Charge the system with pure, high efficiency refrigerant R407C
Skipping these steps can reduce efficiency or cause leaks.
Are There Better Alternatives?
While eco-friendly refrigerant R407C is still widely used, newer low-GWP options are entering the market, such as:
R32 (higher efficiency, but mildly flammable)
R454B (lower GWP, designed to replace R410A)
However, if your system is designed for or retrofitted to R407C refrigerant, it remains a cost-effective and efficient solution—just don’t mix it.
Final Thoughts
R407C is not compatible with other refrigerants. Mixing it with anything else, including R22 or R410A, is unsafe, inefficient, and potentially illegal.
If you're using refrigerant gas R407C, keep it pure.
If you’re switching from another refrigerant, retrofit properly.
And when in doubt, always consult a certified HVAC technician.