R438A Refrigerant Facts & Info Sheet

If you have an old Air conditioning system that uses R22 refrigerant and you want to replace the refrigerant with a non-ozone depleting option, R438A would be an excellent choice. The refrigerant is a HFC blend consisting of five components. They include 8.5% of R32, 45% of R125, 44.2% of R134A, 1.7% of Butane (R600A), and 0.6% of iPentane (R601A).

HVAC technicians usually use R438A as a retrofit replacement for R22. Retrofit replacements require the technician to change the system’s components, including the lubricant, to reduce leaks in your system. Note, though, that the refrigerant is compatible with mineral oil, Alkylbenzene, and Polyolester lubricants. Hence, you don’t need to change the refrigerant oil when retrofitting your system.

The blend has other properties that make it an ideal R22 replacement. And today, we’d like to discuss that in this article. By the end of the article, you should have all the information you need on the refrigerant’s notable features, benefits, limitations, and some of its applications.

Read further if you’d like to learn more.

R438A Facts Table

Name (2):Freon MO99
Name (3):Isceon MO99
Chemistry:R-32/125/134a/600/601a (8.5+.5,-1.5/45?1.5/44.2?1.5/1.7+.1,-.2/.6+.1,-.2)
Status:Active & Growing
Future:Will be phased out in 2024
System Type:Low and medium temperature refrigeration systems
Application:Residential, Commercial, and industrial air conditioning systems
Application (2):industrial and commercial DX Chiller systems
Application (3):Heat pumps
Application (4):Plug-ins & Vending machines
Replacement For:R-22
Ozone Depletion Potential:0
Global Warming Potential:2265
Global Warming Risk:Moderately high
Toxicity Levels:Low degree toxicity
Flammability Levels:Class 1 - No Flame Propagation
Lubricant Required:Mineral oils, POE (most preferred) & PAG Oils
Boiling Point:-43 ?C? or -36.4 ?C ( -45.4 ?F or -33.52 ?F)
Critical Temperature:83.8 ℃
Critical Pressure:41.8 bar
Temperature Glide:6.25K at 1.013 bar
Molar Mass:100.6 g·mol−1
Density:1180 kg/m3 (liquid at saturation 25?C)
Melting Point:Unknown
Vapor Pressure:11.24 bar (25 ?C)
Manufacturers:Various Including: Honeywell, Chemours, Arkema, Mexichem, Chinese, etc.
Manufacturing Facilities:All Over Including: USA, Mexico, EU, China, and others.
Odor:Low concentration: None
EPA Certification Required:Yes
Require Certification to Purchase?Yes
Cylinder Color:Grey

R438A PT Chart

The PT chart (Pressure Temperature chart) is an essential tool for every HVAC technician. Without it, it would be difficult to charge, recover, or even retrofit any system. It could also cost you more money to diagnose the air conditioning system, mainly because some of your system’s components might fail if you use trial and error methods. And in this case, where you’re retrofitting a system, you will need to be careful to avoid this.

Further, each refrigerant in the market has a unique subcool, superheat, and suction pressure value. The document gives you the values to use for that particular refrigerant.

So, once a technician (whether a rookie or professional) completes inspecting the system and knows what refrigerant is used, the next thing is to consult this PT chart for proper evacuation and charging. Here’s the complete PT chart for R438A.


After signing the Montreal Protocol, governments started to phase out HCFC refrigerants such as R22. The refrigerant (R22) was useful and effective in various refrigeration and air conditioning systems. However, the main problem with the refrigerant was that it contained Chlorine, which caused depletion of the ozone layer.

Manufacturers started looking for the best replacements for it, and HFCs and their respective blends became a suitable alternative. A good example is R-438A. It’s a recommended R22 retrofit because of two things, mainly. First, it’s environmentally friendly since it has zero ozone-depleting potential. None of its components has Chlorine in them.

Secondly, it has similar cooling capacities as R22. Compared to other retrofits in the market, experts consider it as one of the most viable replacement.

When replacing the refrigerant, you only need to recover the R22 and charge the system with R438A. You don’t need to change the lubricant since the HFC blend is compatible with mineral oil, alkylbenzene, and polyolester refrigerant oils. However, in our research, we noted that polyolester (POE) was the most preferred since it enhances the flow of the refrigerant.

Note that R438A is a retrofit and not a drop-in replacement. This is because you need to change some of the system’s components, especially those exposed to R22. The solenoid valve, receiver gauges, flange seals, elastomeric seals, and gaskets are good examples of things you might need to change.

Common systems that use this refrigerant include:

  • Ideal for Air conditioning systems with direct expansion evaporators and positive displacement compressors
  • Domestic, industrial, and commercial air conditioning systems
  • DX chiller systems
  • Low and medium temperature refrigerant systems in industrial and commercial spaces


So what are the benefits of using Freon MO99? It does offer the same efficiency as R22. Since R22 and 438A have similar characteristics, your system will last longer and perform at a similar level to R22.

Additionally, no system pressure and temperature point changes are necessary. Not all R22 replacements will offer this benefit, as some can lower the system’s performance and increase energy costs.

For technicians, using this retrofit won’t be a problem because the refrigerant is easy to use. You don’t have to change the oil since it’s compatible with all the three types. If you encounter any problems with the flow, adding POE will solve it completely.

When it comes to conserving energy, 438A has a zero ozone depletion potential. Refrigerants with a higher ODP create a hole in the ozone layer, which exposes living organisms to harmful UV rays from the sun.

Other benefits include:

  • The refrigerant is nonflammable since it has 3% hydrocarbon components
  • It’s non toxic
  • Comes with an A1 safety classification
  • Versatile since it’s useful in a variety of AC systems


Governments around the world are in the process of phasing out HFC refrigerants by 2024. These refrigerants contain Fluorine, a chemical component that causes global warming. Although R438A is efficient, it has a high global warming potential if released into the air the evacuation process or in case of a leak in your system.

Also, note that the refrigerant is not a drop-in replacement. In some systems, changing some system components is necessary to reduce the chances of leakages. Hence, you might use more money to replace the required parts than when using a drop-in replacement.

Since it has a high GWP, you will require an EPA certification to buy and handle the refrigerant. The organization regulates it to prevent inexperienced technicians from releasing or mixing the refrigerant.


There you have it friends. As you can see, R438A is a perfect retrofit replacement for anyone who might have an old system that uses R22. The replacement guarantees long life to your system since it has similar cooling capacity and performance level is as R22.

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