Direct, "drop-in" replacements for R22 are not recommended without modifications, as refrigerants are not universally interchangeable without affecting capacity, pressure, or oil. The best alternatives—such as R438A (MO99), R422B (NU-22), or R427A—are "retrofits." They require reclaiming the old R22 and carefully charging the system in a liquid state.
The best "drop-in" replacements for R22 are R407C for systems equipped with POE oil and R438A (Freon MO99) or R453A (RS-44B) for systems with existing mineral oil. Because true drop-in refrigerants don't exist, minor system retrofitting, such as changing valve cores, may be required.
Comstar RS-44b is the closest, market available drop-in replacement for R22 that requires no oil changes and no system changes. Other features include: Equal Flow Rate & Cooling Capacity as R22.
While true "drop-in" replacements are largely a myth (no alternative performs identically to R22 without adjustments), you can safely retrofit your system. Popular R22 retrofit options include R-453A (RS-44b), R-421A, and MO99 (R-438A).
Since Freon MO99 is the closest capacity match to R-22, compared with most of the other no-oil change refrigerants, it will reach the desired set point before other, lower-capacity refrigerants. With Freon MO99, residents are unlikely to know a different refrigerant is even being used.
The best replacement for R-22 depends on your system's configuration. Because R-22 is fully phased out, the most common drop-in substitutes are R-438A (MO99), R-407C, and RS-44b (R-453A). These allow for system retrofits, though complete system replacement is often recommended for aging units.
Yes, MO99 (also known as R-438A) is a direct, "no-oil-change" drop-in replacement for R-22. It is specifically engineered to replace R-22 in residential and commercial air conditioning, heat pumps, and refrigeration systems.
There are no refrigerants that can be safely or legally mixed directly into a system with R-22. Doing so can cause catastrophic compressor failure, severe pressure inconsistencies, and oil breakdown.
R-22 refrigerant typically costs between $𝟗𝟎 and $𝟐𝟓𝟎 per pound. Because R-22 has been phased out, the supply is dwindling, which causes prices to continuously climb.
January 1, 2025: Manufacturers stopped producing new R-410A residential split systems and heat pumps. Equipment manufactured before this date can still be sold and installed. January 1, 2026: The original deadline for installing R-410A split systems manufactured before 2025.
The most common, modern, and effective "drop-in" replacements for R-22 refrigerant in existing AC systems are R-438A (Freon MO99), R-453A (RS-44b), and R-407C. These alternatives are designed to work with existing mineral oil, often requiring no component changes, though a technician must perform the conversion.
A 30-pound cylinder of R-22 refrigerant is generally worth between $500 and $1,200 to purchase wholesale, and up to $2,400 to $4,500 if bought directly from a service company during a home repair.
While R-407C is the closest match to R-22 in terms of pressures and cooling capacity, it is not a true "drop-in" replacement. You cannot simply pour it into an existing R-22 system without professional modifications and a full evacuation.
Among those products is Freon™ MO99™ (R-438A), a retrofit refrigerant for R-22 that does not require an oil change. Freon™ MO99™ works with: Residential and commercial air conditioning systems (rooftop and indoor packages units, direct expansion chillers, split systems)
A2L refrigerants, the new refrigerants for 2026, will replace R-410A in new systems. A lot about A2L refrigerants is explained in their name: The “A” means low toxicity. The “2L” is a safety classification, indicating it is mildly flammable.
The best drop-in (or near-drop-in) replacements for R-22 are R-438A (Freon MO99), R-422B (NU-22B), and R-453A (RS-44b). These HFC blends allow you to retrofit your system without requiring a full flush of the existing mineral oil.
If you're interested in learning how to refill R22 in your air conditioner, it is important to know that this is not something a homeowner can do on their own. Due to complexity, safety concerns, training and licensing required we do not recommend doing this without having a trained professional onsite.
R22 refrigerant is illegal to import and manufacturer in the U.S. But it's not illegal for anyone to buy R22 freon. And it's not illegal to sell it IF you have a license. As long as the stocks last, you will be able to continue purchasing R22 from specialized dealers and form your air conditioning company.
Technically, there is no true "drop-in" refrigerant that mixes with old R22. The best retrofit alternatives—like RS-44b, R421A, MO99 (R438A), and R422B—require full system evacuation and a new filter drier. These alternatives closely match R22 pressures and run efficiently.
The best replacement for R-22 depends on your system's configuration. Because R-22 is fully phased out, the most common drop-in substitutes are R-438A (MO99), R-407C, and RS-44b (R-453A). These allow for system retrofits, though complete system replacement is often recommended for aging units.
No, you cannot directly replace R-22 with R-410A. They are chemically distinct and cannot be mixed.
R-22 refrigerant typically costs between $𝟗𝟎 and $𝟐𝟓𝟎 per pound. Because R-22 has been phased out, the supply is dwindling, which causes prices to continuously climb.
No, you should never mix MO99 (R-438A) with R-22.
Yes, Freon™ NU-22B™ (R-422B) is a recognized drop-in/retrofit replacement for R-22, but it is not simply a "top-off" solution. Proper conversion requires evacuating all of the old R-22 before charging the system.