Choosing low-GWP refrigerants: Is R448A the right replacement for R404A?

As the refrigeration industry transitions to lower-GWP (Global Warming Potential) refrigerants, many contractors and service technicians are reassessing the refrigerants used in existing R404A systems. GWP values are typically referenced using the Intergovernmental Panel on Climate Change’s (IPCC’s) Fourth Assessment Report (AR4), which remains the benchmark for comparing the environmental impact of refrigerants in many standards, regulations and product specifications. Throughout this guide, GWP values refer to AR4 figures, allowing like-for-like comparison between refrigerant options.

Choosing the right replacement requires balancing environmental impact, system performance, safety classification and retrofit suitability. Among the available options, R448A has emerged as one of the most widely adopted alternatives. This guide explains how R448A compares with other low-GWP refrigerants and when it may be the right choice for your application.

Why are technicians moving away from R404A? 

R404A has been widely used in commercial refrigeration for many years, but its high global warming potential (GWP) has made it a target for phase-down programs worldwide.

Australia's HFC phase-down scheme reduces the amount of high-GWP refrigerants that can be imported over time. As a result, refrigerants with higher GWPs are becoming increasingly expensive and less readily available.

With a GWP of 3922, R404A is one of the highest-GWP refrigerants commonly used in refrigeration systems. Lower-GWP alternatives can help reduce environmental impact while supporting the long-term availability of refrigerants for servicing existing equipment.

What should you consider when choosing a low-GWP refrigerant? 

There is no one-size-fits-all replacement for R404A. Before selecting an alternative, consider:

• Global warming potential (GWP)

• Refrigerant safety classification

• Refrigeration capacity

• Energy efficiency

• Refrigerant glide

• Retrofit requirements

• Manufacturer approvals

• Long-term refrigerant availability

The most suitable refrigerant will depend on the specific application, operating conditions and equipment requirements.

What is R448A? 

R448A is a non-flammable (A1) HFO/HFC blend developed as a lower-GWP alternative to R404A. By combining HFC and HFO refrigerants, R448A delivers a significantly lower GWP while maintaining operating characteristics suitable for many commercial refrigeration applications.

Key benefits of R448A

• Lower GWP than R404A

• Non-flammable A1 safety classification

• Suitable for many retrofit applications

• Similar operating characteristics to R404A

• Strong energy efficiency performance 
  

Comparing low-GWP alternatives to R404A 

Several refrigerants are available as replacements for R404A. The table below compares some of the most common options.

*GWP calculations based on AR4 figures.
 
Note: An A1 safety classification is a cooling fluid classified by the industry as having low toxicity and no flame propagation (non-flammable) under normal conditions.

R448A/R449A  

Best for: Existing R404A systems requiring a lower-GWP retrofit option.

Strengths

• Lowest GWP among common non-flammable R404A replacements

• Similar operating characteristics to R404A

• Good refrigeration capacity

• Strong energy efficiency performance

• Significantly lower GWP than R404A

• Non-flammable, non-toxic A1 classification

• Broad industry adoption

• Suitable for many commercial refrigeration systems 
  

Which is better? 

Both R448A and R449A provide substantial reductions in GWP compared with R404A and are commonly used as retrofit refrigerants. However, R448A is often preferred because it is available from multiple manufacturers, meaning it has better availability. It also has a lower GWP and delivers minor advantages in refrigeration capacity, refrigerant charge size and coefficient of performance (COP).

Is R448A a drop-in replacement for R404A? 

Not necessarily. While R448A can be used in many systems originally designed for R404A, it has a much higher density in liquid phase that may cause the TX valve to overfeed or the solenoid valve to ‘chatter’ meaning the valve may lack the required pressure differential to operate reliably and can repeatedly close and open in rapid succession.

Retrofit requirements vary depending on the equipment and application. Factors to assess include:

• Manufacturer recommendations

• Compressor compatibility

• Expansion device suitability

• Liquid Line and solenoid size may need to be reduced

• Glide in the Evaporator

• Lubricant requirements

• Control settings

• Operating temperatures

Always refer to equipment manufacturer guidance before carrying out a refrigerant conversion. If unsure, talk with an ACTROL Applications Engineer. They’ll guide you on the suitability for retrofit based on the specifics of your job.

Frequently asked questions

What is the GWP of R448A? 
R448A has a GWP of approximately 1,386, compared with 3,922 for R404A.

Is R448A flammable?  
No. R448A has an A1 safety classification, meaning it is non-flammable and has low toxicity.

Does R448A perform similarly to R404A? 
Yes. R448A was developed specifically to provide comparable performance in many commercial refrigeration applications while delivering a significantly lower GWP.

Is R448A better than R449A? 
Both refrigerants are effective lower-GWP alternatives to R404A. R448A is often selected because it can offer improvements in refrigeration capacity, charge size and efficiency and is available from multiple manufacturers globally.

Can existing R404A systems be converted to R448A? 
Many can, but retrofit requirements vary. Equipment manufacturer recommendations should always be reviewed before converting a system.

Do I need to change the TX Valve when converting from R404A to R448A?
Yes. While similar to R404A in refrigeration capacity, R448A is much denser in liquid phase and operates at different temperature and pressures to R404A. If you reuse the R404A valve it will ‘hunt’ and overfeed thereby increasing the likelihood of mechanical failure. Consideration should also be given to correct selection of a liquid line solenoid valve.

Can I use R448A on low temperature systems? 
Yes. In most cases, R448A will operate in low temperature applications – albeit with a higher heat of compression than R404A. In systems operating with poorly sized condensers or sustained high ambient conditions, additional cooling may be required to prevent oil being exposed to temperatures above 107°C. Strategies like liquid injection of head cooling fans may be required in some applications. If unsure talk to an Applications Engineer.

Which refrigerant should you choose?

If you’re unsure of retrofit suitability, always consult manufacturer recommendations or speak with an ACTROL Applications Engineer.

Pro tip 
Don't focus solely on GWP when selecting a replacement refrigerant. Capacity, energy efficiency, glide and equipment compatibility can all affect long-term system performance. The best refrigerant is the one that balances environmental considerations with the requirements of the application.

The bottom line 

There is no single low-GWP refrigerant that suits every application. The right choice depends on the system design, operating conditions and manufacturer recommendations. For many existing R404A systems, R448A has become one of the most widely adopted retrofit options because it combines a significantly lower GWP with a non-flammable safety classification and strong refrigeration performance. When considering any refrigerant change, always verify retrofit requirements and equipment approvals before proceeding.

Need help selecting the right refrigerant for a retrofit project? Speak to your local ACTROL branch team for technical advice and product availability.