If your system still runs on R22, you already know it’s time to switch. R422B is one of the easiest drop-in replacements available today.
In this guide, you’ll see R422B’s performance, pros and cons, and applications. You can quickly determine if it’s the right choice for your system.
What Is R422B Refrigerant?
R422B is a refrigerant you can use to replace R22 without major system changes. It’s also sold as NU-22B.
It has an A1 safety rating, which means it is non-toxic and non-flammable. That makes it safe for most commercial and residential systems.
R422B is a blend of R125, R134a, and a small amount of R600a to balance pressure, efficiency, and system compatibility. It contains no chlorine and has zero ODP, so it won’t damage the ozone layer.
Properties of R422B Refrigerant
Physical Properties
Density
At standard temperature and pressure, R422B is a colorless, transparent gas with no pungent odor. It is heavier than air, so it won’t rise if a leak occurs. Instead, it collects near the floor. When you check for leaks, focus on low areas like the machine room floor.
Critical Parameters
R422B works at similar pressure levels as R22. This ensures you can use it in your R22 systems directly without major system changes. And you shouldn’t experience a sudden drop in performance at critical conditions.
Water Solubility
R422B does not mix with water easily. At 25°C, its solubility in water is only 0.12 g/L, making it virtually insoluble. This helps prevent ice from forming inside your system.
You can see the properties of R422B:
| Feature | R422B Refrigerant |
| Composition | 56 % R-125
42.5 % R134a 1.5 % R600a |
| Molecular Weight | 92.1 |
| Boiling Point (1atm, ℃) | -46.3 |
| Critical Pressure (MPa) | 4.08 |
| Critical Temperature (℃) | 72 |
| Critical Density (lb./ftˆ3) | 32.9 |
| Liquid Density (70˚F, lb./ftˆ3) | 73.05 |
| Vapor Density (bp.lb./ftˆ3) | 0.363 |
| Heat of Vaporization (bp, BTU/lb.) | 84.2 |
| Specific Heat Liquid (70 ˚F, BTU/lb. ˚F) | 0.3385 |
| Specific Heat Vapor (1atm, 70 ˚F, BTU/lb. ˚F) | 0.201 |
| ODP | 0 |
| GWP | 2526 |
| Safety Rating | A1 |
| Temperature Glide (˚F) | 5 |
| Oil | MO & AB & POE |
Chemical Properties
Stability
Under normal conditions, R422B stays stable. It won’t break down, create acids, or damage your compressor.
When operated long-term within a sealed refrigeration system, it does not decompose to produce acidic substances or toxic gases.
It contains no chlorine atoms. You can run it long-term without worrying about chemical breakdown or system damage.
Safety
R422B refrigerant has an A1 safety rating. This means it is non-toxic and non-flammable. You can safely use it in most commercial and residential systems.
Its Ozone Depletion Potential (ODP) is 0, and its Global Warming Potential (GWP) is 2526.
R422B Refrigerant Pressure Temperature Chart
| Temp ( ˚F) | Temp (℃) | Pressure Liquid (psig) | Pressure Vapor (psig) |
| -40 | -40 | 0.9 | 2.7″ |
| -35 | -37.2 | 3 | 0.9″ |
| -30 | -34.4 | 5.4 | 1.1 |
| -25 | -31.7 | 7.9 | 3.2 |
| -20 | -28.9 | 10.7 | 5.7 |
| -15 | -26.1 | 13.8 | 8.3 |
| -10 | -23.3 | 17.1 | 11.3 |
| -5 | -20.6 | 20.7 | 14.5 |
| 0 | -17.8 | 24.7 | 18 |
| 5 | -15 | 29 | 21.9 |
| 10 | -12.2 | 33.6 | 26.1 |
| 15 | -9.4 | 38.6 | 30.6 |
| 20 | -6.7 | 43.9 | 35.5 |
| 25 | -3.9 | 49.7 | 40.8 |
| 30 | -1.1 | 55.9 | 46.6 |
| 35 | 1.7 | 62.5 | 52.7 |
| 40 | 4.4 | 69.6 | 59.4 |
| 45 | 7.2 | 77.2 | 66.5 |
| 50 | 10 | 85.3 | 74.1 |
| 55 | 12.8 | 94 | 82.2 |
| 60 | 15.6 | 103 | 90.9 |
| 65 | 18.3 | 113 | 100 |
| 70 | 21.1 | 123 | 110 |
| 75 | 23.9 | 134 | 120 |
| 80 | 26.7 | 145 | 132 |
| 85 | 29.4 | 158 | 143 |
| 90 | 32.2 | 170 | 156 |
| 95 | 35 | 184 | 169 |
| 100 | 37.8 | 198 | 183 |
| 105 | 40.6 | 213 | 198 |
| 110 | 43.3 | 229 | 213 |
| 115 | 46.1 | 246 | 230 |
| 120 | 48.9 | 263 | 247 |
| 125 | 51.7 | 281 | 265 |
| 130 | 54.4 | 301 | 284 |
| 135 | 57.2 | 321 | 304 |
| 140 | 60 | 342 | 326 |
Advantages of R422B Refrigerant
0 ODP
R422B contains absolutely no chlorine atoms and has an ODP value of 0. It eliminates the ozone-depleting properties of R22 and complies with the environmental regulations of the Montreal Protocol and the Kigali Amendment. You can use it with confidence in both new installations and retrofits of existing equipment. This helps you meet current environmental regulations without issues.
Easy Drop-in Replacement for R22
You can switch from R22 to R422B without changing your compressor, piping, or controls.
That means lower cost and faster retrofit.
R422B’s operating pressure and application range are highly compatible with those of R22. R422B refrigerant delivers similar cooling performance to R22. You won’t see a noticeable drop in capacity after switching.
Its liquid and gas densities are compatible with the piping design of traditional R22 systems, preventing issues such as insufficient flow or excessive pressure drop.
Low Temperature Drift
R422B refrigerant exhibits significantly lower temperature drift than typical non-azeotropic refrigerants. During evaporation and condensation, temperature changes are limited to just 1–2°C. This does not affect the heat exchange efficiency of the evaporator and condenser, nor does it cause abnormal fluctuations in the system’s suction temperature.
When you start the system, you can use the same settings as R22 without adjusting your system settings.
Strong Compatibility
In addition to being compatible with various lubricants, R422B refrigerant is also compatible with all sealing materials, metal components, and dry filters used in R22 systems, causing no damage to the system.
The operational procedures for charging, recovery, leak detection, and maintenance are identical to those for R22. Your existing operations and maintenance team can operate the system proficiently without the need for retraining, eliminating equipment failures caused by operational errors.
Drawbacks of R422B Refrigerant
High GWP
R422B has a GWP of 2,526. While it complies with current environmental regulations, some regions are already limiting its use because of its high GWP.
In the long term, it’s not future-proof, although it works well today. It is more suitable for short- to medium-term retrofits of existing R22 equipment. If you are installing new high-end equipment with an expected service life exceeding 15 years, R422B is not the right choice. Alternatives with lower GWP (such as R454B and R452B) are likely to gradually replace it.
Limited to Use in Medium-Temperature
R422B is best suited for medium-temperature refrigeration and air conditioning applications (temperatures ranging from -15°C to 7°C).
In low-temperature refrigeration applications where the evaporation temperature is below -20°C, its cooling capacity and COP will decrease, while the compression ratio will rise markedly. This leads to high compressor discharge temperatures and overloading, which can shorten the compressor’s service life.
It cannot be used in low-temperature cold storage facilities, quick-freezing equipment, or low-temperature refrigeration systems. This is a standard you must consider during selection.
The critical temperature of R422B is about 72°C. At high temperatures, the condensing pressure of R422B will be higher than that of R22, and the system’s COP may decrease slightly. If your equipment operates year-round under extreme high temperatures, this factor requires evaluation.
Leakage Issues
Although R422B exhibits minimal temperature glide, it is still a blended refrigerant rather than a single-component refrigerant.
If a leak occurs in the system, the refrigerant components will undergo slight separation, leading to a decline in performance.
In this case, you can’t top off R422B like R22. You must completely recover the remaining refrigerant from the system, perform a vacuum, and then recharge it with new R422B refrigerant. If you skip this step, your system may lose efficiency or even damage the compressor.
Recovery and Reuse Performance
As a blended refrigerant, R422B is more difficult to recover, regenerate, and purify than single-component refrigerants such as R22. The component ratios of the regenerated refrigerant are easy to deviate, resulting in a decline in performance. Recovery and regeneration are not cost-effective and will increase costs in the long run.
Applications of R422B Refrigerant
You can use R422B in the following applications:
- Retrofit of existing R22 residential and commercial air conditioning systems: residential air conditioners, packaged air conditioners, rooftop air conditioning units, etc.
- Medium-temperature commercial refrigeration equipment: supermarket refrigerated display cases, beverage refrigerators, commercial freezers, convenience store fresh-keeping cabinets, kitchen refrigeration equipment, etc.
- Small and medium-sized industrial medium-temperature refrigeration units: industrial process cooling units, injection molding machine cooling systems, hydraulic oil cooling units, central air conditioning chillers, etc.
- Transportation refrigeration equipment: Automotive air conditioning, construction vehicle air conditioning, medium-temperature refrigeration systems for refrigerated trucks, etc.
Warning
R422B refrigerant can’t be used at very low temperatures. Warning about the following tips:
- You should not use R422B in low-temperature applications below -20°C, including quick-freezing cold storage, low-temperature freezers, medical ultra-low temperature freezers, industrial freezing units, and other equipment. Using it in such applications will directly cause the compressor to overheat and fail.
- R422B is not recommended for new, high-end, eco-friendly equipment designed to achieve lower GWP. Such applications are better suited to ultra-low-GWP refrigerants such as R454B and R438A.
- R422B is also not recommended for large centrifugal chillers. These are better suited for dedicated centrifugal refrigerants.
If you choose the wrong application, you risk serious system damage and higher costs.
What should you keep in mind when switching from R22 to R422B?
Switching to R422B is simple:
- No need to replace the compressor, heat exchanger, piping, or pressure protection devices.
- No adjustment of system control parameters, and certainly no need to replace the existing lubricant.
- Simply evacuate the existing R22 and charge the system with R422B for normal operation.
In most cases, you can finish the retrofit in just a few hours instead of several days. Labor and material costs are reduced by over 70%. If you have a large number of R22 systems, R422B is ideal for bulk upgrades of existing R22 equipment. This is why many contractors choose R422B for fast upgrades.
Final Thoughts
R422B is one of the easiest and most cost-effective ways to replace R22. It’s not a long-term solution, but it works well for existing systems. If you want a fast, low-risk upgrade, R422B is a good choice.
FAQ
Is R422B a direct replacement for R22?
Yes. You can use R422B as a drop-in replacement for most R22 systems without changing.
What should you do when retrofitting a system to R422B?
If you have used R22 refrigerant in your system before, you should recover the remaining R22.
Is R422B still allowed in the US?
If you live in California or New York, R422B refrigerant has been restricted since January 1, 2025, because of its high GWP.
Can R422B be used in low-temperature systems?
No. It is not suitable for low-temperature systems, but is used in middle temperatures.
What happens if R422B leaks?
You must recover and recharge the system completely. You cannot top it off.
You may also find this related blog post very useful:
Which gas is used in air conditioners?
What is refrigerant, the-ultimate-guide?
About The Author
Evan Wang
I am Evan Wang, the General Manager, Marketing Director, and SEO Expert at Sunnyda Cold Room. I have over 20 years of experience in the refrigeration industry, and my expertise is in commercial refrigeration solutions.
I’d be delighted to share practical ideas about refrigeration products, project selection, export trade, SEO, and marketing.
Let’s connect!
