R-22, also known as HCFC-22 or by its brand name Freon, has been the refrigerant of choice from as early as the 1930s when it was developed by DuPont and General Motors.
It has excellent refrigeration properties and unlike earlier refrigerants like ammonia it was found to be non-toxic. As we write this, R-22 has been phased out in favor of R-410A. What happened to R-22?

It was discovered that R-22 was quite harmful on the environment as it furiously depleted the ozone layer resulting in global warming. As a matter of fact, it is believed that R-22 is 2000 times more potent in ozone layer depletion than carbon dioxide.
Being a signatory to the Montreal Protocol, United States Environmental Protection Agency (EPA) banned the manufacture of Freon-using air conditioners in 2010. The last R-22 batch was produced or imported in January of 2022.
The difference between R-22 and R-410A is that R-22 is an ozone-depleting HCFC while R-410A is an HFC and doesn’t deplete the ozone layer. R-410A operates at a higher pressure and is a better at absorbing and releasing heat and hence higher efficiency than R-22.
New air conditioners are now made to use R-410A. R-22 from stockpiles or even recycled from old units will still be available to service other old AC units although the supply will run out in a few years and it is also quite expensive.
Read more on the ban of R-22 and the options available for old AC units in this post.
Note: It is not illegal to own an air conditioner that still uses R-22. You can even get recycled R-22 or some from old stock to recharge you old air conditioner if it is leaking.
R-22 vs R-410A
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Can You Put R-22 in an R-410A System?

Unfortunately, you can’t simply add R-410A in an air conditioners that was designed to use R-22. You would need to have the air conditioner retrofitted by a licensed technician but as some homeowners have found out, the cost is not that different from buying a new unit.
You can’t replace R-22 with R-410A in an AC system. The 2 refrigerants not only have different thermodynamics properties and operating pressures, but also use different lubrication oils and therefore incompatible. You can however have the AC retrofitted or replaced it altogether.
R-22 and R410A should not be mixed together. R-410A operates at a higher pressure than R-22, meaning that your compressor will be trying to compress 2 refrigerants at the same time. Needless to say, your cooling system will be ineffective and will not last long.
If you mix R-22 and R-410A or if you replace R-22 with R-410A, your cooling system will rupture. Unlike R-22, R-410A operates at a much higher pressure which will overwhelm the parts which are made to only withstand R-22 pressure.
The price of R-410A is way cheaper compared to that of R-22 which can be attributed to the ban on R-22. For context, a pound of R-22 can be as high as $100 while a similar amount of R-410A is about $30. Soon R-22 will not be available anywhere.
R-410A isn’t necessarily colder than R-22 but due to its high efficiency it will make the air in a room cool slightly quicker than R-22. It is also worthwhile to note that R-410A is more energy-efficient than R-22.
Let us now look at the main differences between R-22 and R-410A in more details
Chemical Composition
Freon, or R-22 is a di-fluorochloromethane (HCFC-22) with its chemical formula being CHCLF2. It is thus a hydrogen-containing chlorofluorocarbon (CFC) and hence its greenhouse effect on the environment.
R-410A is a hydrofluorocarbon (HFC) made up of equal parts of R-32 and R-125 with its chemical formula being CH₂F₂ + CHF₂CF₃.
Effects on the Environment
One important thing to note from the chemical compositions of the two refrigerants is that R-22 is a chlorofluorocarbon (CFC) while R-410A is a hydrofluorocarbon (HFC). This means that R-22 contains chlorine while R-410 doesn’t.
As a matter of fact, HFCs were originally made to replace CFCs and HCFCs. This is because they trap and absorb heat or infrared radiation in the lower atmosphere of the earth.
Although R-22 is a HCFC (less-zone depleting potential) and not a CFC (worse), it still causes ozone later depletion over time.
In fact, the United Nations Environmental Program (UNEP) estimates that HCFCs global warming potential is as high as 2000 times that of carbon dioxide.
R410A does not contain chlorine atoms and will therefore not deplete the ozone layer. More studies are however being done on it.
Performance as a Refrigerant
Apart from its effect on the environment, most people didn’t have complains about R-22 in as far as its performance was concerned. So, how does R-410A fair?
As you would expect, the newer R-410A’s performance is slightly better than that of R-22. It is also more-efficient, cools the air quicker and is therefore energy-efficient as well.
R-410A is better at absorbing heat from the house and releasing it outdoors. As such, the air conditioning compressor has sufficient time to cool off which prevents it from burning out due to overheating.
As I had mentioned, R410-A operates at a much higher pressure than R-22. AC compressors made to use R-410A are therefore able to withstand more stress without the likelihood of cracking.
That is why if you were to put R-410A in an R-22 AC unit the system would just rupture due to the high pressure.
Recharging/Top Off

Most people are familiar with the process involved when an air conditioner running on R-22 leaks. An HVAC technician will simply fix the leak then top off the refrigerant to the required amount. That can be done it its gas or liquid state.
Things work a little different with R-410A. as you know by now, R-410A is a basically a blend of different chemicals with different pressures and different size molecules as well.
If you R-410A AC systems is leaking, it means different amounts of the chemicals are leaking and therefore a top off is not only ill-advised but it is also not allowed. If the system leaks, the remaining refrigerant will need to be removed and recycled before recharging the system with the refrigerant, specifically in its liquid state.
Lubricating Oils
Another reason why you just can’t put R-410A in an AC system made to use R-22 is because the two refrigerants need different lubricating oils.
Air conditioning systems need oil to lubricate the moving parts of the compressor and expansion valve. While R-22 uses mineral oil, R-410A uses synthetic oil, which is the same oil you would find in jet engines.
Price
With production of R-22 already stopped and the supply from stockpiles dwindling, the price of R-22 is at an all-time high. As expected, there will be no Freon to buy in the coming years.
It is therefore not a wonder that the price of R-22 is way higher compared to that of R-410A. For context, R-22 is at least 3 times more expensive than R-410A.
Conclusion
Having stated all of the above, I should as well add that there is usually a disconnect between policy makers and the general public. Why do I say that?
Air conditioners that use Freon are very good at cooling and removing humidity from a room and are/were cheaper to run in the long run. On the other hand, air conditioners using R-410A are expensive to run.
There are many homeowners who have found that they need the services of an HVAC technician more frequently with R-410A AC systems more than they did with R-22 AC systems. Some have also said that the new air conditioners do a bad job at removing humidity from the house.
It goes without saying that the race to find a great refrigerant is far from over.