A practical guide to compliant, cost-effective refrigerant alternatives for legacy air conditioning and refrigeration systems
Inside this guide
• What R22 replacement refrigerants are and how they work
• The regulatory timeline behind the R22 phase-out
• Benefits of modern alternatives and drop-in compatibility
• A closer look at RS-70, MO99 and R407C
• Retrofit considerations and the professional conversion process
• Compliance, sustainability and choosing the right path forward
· OVERVIEW
Introduction
R22 refrigerant, also known as HCFC-22, was widely used in air conditioning and refrigeration systems for many years due to its reliable cooling performance and energy efficiency. However, because R22 contributes to ozone depletion and has a high environmental impact, its production and use have been phased out across many countries, including the UK and Europe.
As a result, businesses and homeowners operating older HVAC systems now face increasing maintenance costs, refrigerant shortages, and compliance concerns. Modern R22 replacement solutions provide a practical solution that allows existing systems to continue operating without the immediate expense of full equipment replacement.
What Is an R22 Replacement?
An R22 replacement refrigerant is an alternative gas designed to replace R22 in older air conditioning and refrigeration systems. These replacement refrigerants are formulated to deliver similar cooling performance while reducing environmental impact and complying with modern regulations. Most replacement refrigerants are classified as:
• Drop-in replacements
• Retrofit refrigerants
• Lower Global Warming Potential (GWP) alternatives
• Non-ozone-depleting refrigerants
Popular alternatives include R453A (RS-70 / RS-44b), R407C, R422D, and R438A (MO99).
· BACKGROUND
Why R22 Was Phased Out
R22 belongs to a category of refrigerants called HCFCs (Hydrochlorofluorocarbons), which have been linked to ozone layer depletion. International environmental agreements such as the Montreal Protocol led to the gradual phase-out of HCFC refrigerants.
Key Regulatory Milestones
Year Regulation Impact
2010 Virgin R22 banned for servicing and maintenance
2015 onward Reclaimed R22 heavily restricted and increasingly unavailable
The Resulting Impact - The phase-out has caused:
• Rising refrigerant prices
• Reduced availability
• Difficulty sourcing compatible components
• Increased maintenance expenses for older systems
Benefits of Modern R22 Replacement Refrigerants
1. Lower Environmental Impact
Modern refrigerants are designed with lower ozone depletion potential and reduced environmental harm compared to traditional R22. Some alternatives also offer:
• Lower Global Warming Potential (GWP)
• Improved energy efficiency
• Better regulatory compliance
Industry Note
RS-70 (R453A), for example, is marketed as one of the lowest GWP drop-in replacements for R22.
2. Drop-In Compatibility
Many R22 replacement refrigerants are designed as “drop-in” alternatives, meaning they can often be used with minimal system modifications. Advantages include:
• Reduced downtime
• Lower retrofit costs
• Minimal equipment changes
• Faster servicing
Certain products are compatible with existing mineral oils and alkylbenzene lubricants, reducing the need for complete oil replacement.
3. Extended Equipment Life
Replacing R22 with a compatible refrigerant can significantly extend the life of existing HVAC equipment, delaying the need for costly full-system replacement. This is especially valuable for:
• Commercial buildings
• Retail stores
• Warehouses
• Industrial refrigeration systems
• Older residential air conditioning systems
4. Improved Serviceability
Because R22 is increasingly scarce and expensive, many HVAC engineers now recommend conversion to approved alternatives for easier maintenance and future servicing. Several technicians in HVAC communities report commonly using alternatives such as:
• R422B
• R422D
• R438A (MO99)
• R407C
• R453A
04 · PRODUCT PROFILES
Common R22 Replacement Refrigerants
Below are three of the most widely used alternatives, each suited to slightly different applications and budgets.
RS-70 R453A
RS-70 is a non-flammable drop-in refrigerant designed specifically as an R22 replacement for both air conditioning and refrigeration applications.
KEY FEATURES
▸ Similar cooling capacity to R22
▸ Comparable operating pressures
▸ Lower GWP than many alternatives
▸ Compatible with existing lubricants
▸ Suitable for capillary and TXV systems
MO99 R438A
MO99 is widely used as a retrofit solution for older R22 systems. Many HVAC professionals recommend it as a practical and cost-effective replacement.
ADVANTAGES
▸Good compatibility with existing systems
▸ Widely available
▸ Suitable for residential HVAC applications
▸ Lower servicing complexity
R407C is another popular alternative commonly used in retrofitted systems, though it typically requires more involved system preparation.
IMPORTANT NOTES
▸ Often requires oil changes
▸ System flushing may be necessary
▸ May involve gasket replacement
▸ Slight cooling capacity reduction possible
Important Considerations Before Retrofitting
Before replacing R22 refrigerant, several technical factors should be assessed.
System Age: Very old systems may not justify retrofit costs if:
• Compressors are failing
• Corrosion is severe
• Energy efficiency is poor
In some cases, full replacement may be more economical long term.
Oil Compatibility: Different refrigerants require different lubricants. Some refrigerants:
• Work with mineral oil
• Require POE oil
• Need partial oil replacement
• Require gasket or seal upgrades
R407C Retrofit Alternative
Technicians often recommend checking oil compatibility before conversion.
Performance Changes: After retrofit:
• Cooling capacity may slightly decrease
• Operating pressures can change
• TXV adjustments may be required
• System efficiency can vary Best Practice
Professional commissioning and testing are essential after every retrofit to verify safe and efficient operation.
06 · DIAGNOSTICS
Signs Your System May Need an R22 Replacement
Common indicators include:
• Rising energy bills
• Poor cooling performance
• Refrigerant leaks
• Compressor issues
• Expensive maintenance costs
• Difficulty sourcing R22
If your system still relies on R22, proactive replacement planning can reduce future downtime and emergency repair costs.
07 · CONVERSION
Professional Retrofit Process
A typical R22 retrofit follows a structured sequence carried out by qualified HVAC engineers:
01 System Inspection
Full assessment of the existing installation and components.
02 Leak Testing
Identify and resolve any refrigerant leaks before charging.
03
04
05
06
07
Refrigerant Recovery
Safely reclaim existing R22 in line with regulations.
Oil Compatibility Assessment
Confirm or replace lubricants to suit the new refrigerant.
Component Checks
Inspect gaskets, seals, expansion valves and filter driers.
Refrigerant Charging
Charge the system with the selected R22 alternative.
Pressure Testing
Verify operating pressures match design specifications.
08 Performance Verification
Commission the system and confirm reliable cooling output.
Professional HVAC engineers should always perform refrigerant conversions to ensure:
• Safety
• Compliance
• Correct charging
• Reliable operation
08 COMPLIANCE
Environmental and Regulatory Compliance
Modern refrigerants help businesses align with:
• F-Gas regulations
• Environmental sustainability targets
• Energy efficiency goals
• Refrigerant management requirements
The Wider Benefit
Upgrading from R22 can also help reduce carbon footprint and improve operational efficiency supporting both environmental and commercial objectives.
Conclusion
R22 replacement refrigerants provide a practical and cost-effective solution for maintaining older air conditioning and refrigeration systems. With R22 becoming increasingly unavailable and expensive, switching to a compatible alternative helps extend equipment lifespan, reduce maintenance costs, and improve environmental compliance.
Solutions such as RS-70 (R453A), MO99 (R438A), and R407C offer varying benefits depending on system design, budget, and performance requirements. Choosing the correct refrigerant and working with experienced HVAC professionals ensures safe operation and long-term reliability.
Key Takeaway
For businesses and property owners still operating R22 systems, proactive retrofit planning is now an essential step toward maintaining efficient and compliant cooling systems for the future.
