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Refrigerants are essential to refrigeration, air conditioning, cold storage, food preservation, pharmaceutical storage, industrial cooling and heat-pump systems. However, not all refrigerants have the same environmental impact or regulatory status.
Over the past several decades, the refrigeration industry has moved away from refrigerants that damage the ozone layer and is now increasingly moving away from refrigerants with high global warming potential (GWP).
The Montreal Protocol and its amendments have been central to this transition. Chlorofluorocarbons (CFCs) were phased out because of their ozone-depleting properties, while hydrochlorofluorocarbons (HCFCs) are being phased out. Hydrofluorocarbons (HFCs), although they do not deplete the ozone layer, are being phased down because many have high global warming potential.
For businesses purchasing refrigeration or air-conditioning equipment, therefore, it is important to understand whether a refrigerant is:
There are two major environmental concerns associated with refrigerants:
Some older refrigerants contain chlorine or bromine that can contribute to the destruction of stratospheric ozone.
CFCs were particularly damaging to the ozone layer. HCFCs were subsequently used as transitional alternatives because they have lower ozone-depletion potential than CFCs, but they still damage the ozone layer.
This led to the international phase-out of CFCs and the ongoing phase-out of HCFCs under the Montreal Protocol.
Many newer refrigerants were developed as replacements for CFCs and HCFCs. HFCs do not deplete the ozone layer, but several HFC refrigerants have very high GWP.
For example, R-404A has a much higher climate impact than low-GWP alternatives such as carbon dioxide, ammonia and hydrocarbons.
The Kigali Amendment therefore established a global framework for reducing HFC consumption and encouraging the adoption of lower-GWP technologies.
It is important to use the term “globally phased out” carefully. International agreements establish global obligations, but national laws determine exactly how those obligations are implemented. Some historical substances may also have narrowly defined essential-use or other exemptions.
The best-known examples include:
| Refrigerant | Chemical family | Typical historical application | Current status |
|---|---|---|---|
| R-11 | CFC | Large chillers and foam blowing | Phased out |
| R-12 | CFC | Refrigerators, freezers and automotive AC | Phased out |
| R-13 | CFC | Low-temperature refrigeration | Phased out |
| R-113 | CFC | Refrigeration/industrial applications | Phased out |
| R-114 | CFC | Specialized refrigeration | Phased out |
| R-115 | CFC | Component of R-502 | Phased out |
CFCs are controlled substances under the Montreal Protocol because of their ozone-depleting properties.
R-12 (dichlorodifluoromethane) was historically widely used in domestic refrigerators, freezers and vehicle air-conditioning systems.
It has since been replaced by alternatives including R-134a and, increasingly, lower-GWP alternatives depending on the application.
R-11 was widely used in large centrifugal chillers and other applications.
Modern systems use alternatives with substantially lower environmental impact.
The phase-out of CFCs does not mean that every old piece of equipment containing a CFC automatically has to be destroyed. Existing equipment and recovered refrigerant can be subject to specific national rules concerning recovery, recycling, reclamation and disposal.
Releasing old refrigerant into the atmosphere is not an acceptable servicing practice.
Hydrochlorofluorocarbons (HCFCs) were introduced as transitional refrigerants after CFCs.
The most familiar example is:
R-22 (HCFC-22) has historically been one of the most widely used refrigerants for:
However, R-22 is an ozone-depleting substance and is being phased out under the Montreal Protocol.
For developing countries operating under Article 5 of the Montreal Protocol, the international schedule requires complete HCFC phase-out by 2030, subject to the Protocol’s specific provisions and exemptions.
This means that R-22 should not be considered a long-term refrigerant for new refrigeration installations.
R-123 is another HCFC historically used particularly in centrifugal chillers.
It is also subject to the HCFC phase-out.
An existing R-22 refrigeration or air-conditioning system may continue to operate where national regulations permit it. However, businesses should consider the long-term availability and regulatory direction of the refrigerant before investing heavily in an old R-22 system.
For a new installation, selecting a refrigerant that aligns with the long-term regulatory direction is generally a better approach.
This is where there is often considerable confusion.
HFC refrigerants are not the same as CFCs and HCFCs.
They do not deplete the ozone layer, but many HFCs have high GWP.
The Kigali Amendment therefore established a global phase-down, rather than a blanket worldwide prohibition of every HFC refrigerant. The exact reduction schedule differs between groups of countries.
Some important HFC refrigerants include:
| Refrigerant | Common application | General direction |
|---|---|---|
| R-134a | Refrigeration, chillers, automotive AC | Increasingly restricted in some markets |
| R-404A | Commercial and industrial refrigeration | Strongly being replaced |
| R-507A | Low-temperature refrigeration | Being replaced |
| R-407C | Air conditioning | Increasing restrictions in some markets |
| R-410A | Air conditioning/heat pumps | Transitioning to lower-GWP alternatives in many markets |
| R-32 | Air conditioning/heat pumps | Lower-GWP HFC, but still subject to HFC phase-down |
The important point is that HFC phase-down does not mean every HFC is currently illegal worldwide.
R-404A became extremely popular in commercial refrigeration, cold rooms, freezers and low-temperature applications.
However, its GWP is very high compared with modern alternatives.
Consequently, many markets are moving away from R-404A.
Potential alternatives depend on the equipment and application and can include:
UNEP identifies ammonia, carbon dioxide, hydrocarbons, HFOs and lower-GWP HFC blends among the major alternative refrigerant technologies being adopted as HCFCs and high-GWP refrigerants are transitioned out.
R-410A has been widely used in split air conditioners, heat pumps and other air-conditioning equipment.
It does not deplete the ozone layer, but its GWP is significantly higher than that of newer alternatives.
As regulations increasingly target high-GWP refrigerants, manufacturers in many markets are transitioning toward refrigerants such as:
The appropriate replacement depends on equipment design, operating pressure, safety classification, efficiency and applicable regulations.
There is no single refrigerant that is “fully accepted worldwide” for every application.
A refrigerant can be environmentally favourable but still be unsuitable for a particular machine because of:
Nevertheless, several low-GWP refrigerants are widely recognised as important long-term alternatives.
R-717 (ammonia) has a GWP of approximately zero and has been used in industrial refrigeration for many decades.
It is particularly suitable for applications such as:
Ammonia is highly efficient, but it is toxic and requires properly designed systems and trained personnel.
R-744 (carbon dioxide) has a GWP of 1 under the conventional 100-year GWP reference used for refrigerants.
COâ‚‚ is increasingly used in:
Its major advantage is extremely low environmental impact compared with high-GWP synthetic refrigerants.
However, COâ‚‚ systems operate at relatively high pressures and must be designed specifically for COâ‚‚ operation.
R-290 (propane) is a hydrocarbon refrigerant with extremely low GWP.
It is used in applications including:
Its principal challenge is flammability. R-290 is classified as A3, meaning it is highly flammable, so equipment must be designed and installed according to applicable safety requirements.
The European Commission identifies R-290, R-717 and R-744 among climate-friendly refrigerant alternatives.
R-32 is an HFC refrigerant with a substantially lower GWP than R-410A.
It is widely used in modern air-conditioning and heat-pump equipment.
However, R-32 is still an HFC and therefore remains within the broader global HFC phase-down framework. It should therefore not be described as a completely regulation-free refrigerant.
R-32 is classified as A2L, meaning it has lower flammability.
Hydrofluoroolefins (HFOs), such as R-1234yf and R-1234ze(E), were developed as very-low-GWP alternatives for certain applications.
They are used in various refrigeration, air-conditioning, automotive and industrial applications.
The European Commission lists HFOs and low-GWP HFO/HFC blends among the alternative technologies being used to reduce the climate impact of refrigeration and air-conditioning.
The refrigeration industry can broadly be understood as follows:
Examples:
These are CFC refrigerants and have been phased out under the international ozone-protection regime.
Examples:
HCFCs are being eliminated because they deplete the ozone layer.
Examples include:
The exact regulatory restrictions depend on the refrigerant, application and country.
Examples include:
These refrigerants are important in the industry’s transition toward lower environmental impact.
There is an important misconception that there is a universal list of refrigerants that are completely unrestricted everywhere in the world.
There is no such universal list.
A refrigerant can be internationally recognised as an environmentally preferable option while still being subject to national, regional, equipment-specific or safety regulations.
For example:
UNEP specifically notes that refrigerant alternatives must be evaluated according to performance, cost, availability, toxicity, flammability, operating pressure, GWP and energy efficiency.
Therefore, the correct question is not simply:
“Which refrigerant is legal worldwide?”
A better question is:
“Which refrigerant is technically suitable, safe, commercially available and compliant with the regulations applicable to this particular project?”
When constructing a new cold room, freezer, blast freezer, cold warehouse or industrial refrigeration system, refrigerant selection should be considered at the design stage.
The refrigerant affects:
For this reason, simply selecting a refrigerant because it is currently cheap or readily available may not be the best long-term decision.
A refrigeration system can remain in service for many years. Selecting a refrigerant with a favourable long-term regulatory outlook can reduce the risk of future servicing and refrigerant-availability problems.
The regulatory transition is not occurring at the same speed everywhere.
Under the Montreal Protocol, developing countries are progressing through the HCFC phase-out, while the Kigali Amendment establishes HFC phase-down schedules. For Article 5 Group 1 countries, for example, the HFC freeze began in 2024, followed by a 10% reduction in 2029 and progressively larger reductions thereafter.
Regulations in individual markets can be considerably stricter.
For example, the European Union’s F-gas Regulation has introduced restrictions on high-GWP fluorinated gases in refrigeration and air-conditioning equipment. The EU rules include restrictions on servicing equipment with F-gases above specified GWP thresholds and additional restrictions on placing certain refrigeration equipment on the market.
This demonstrates why an international refrigerant transition should not be interpreted as meaning that every country has exactly the same prohibition date.
Businesses planning to install:
should consider the entire life cycle of the refrigeration equipment, rather than only its initial purchase price.
A suitable refrigerant should ideally provide:
For large industrial refrigeration projects, refrigerant selection should be part of the engineering design rather than an afterthought.
The refrigeration industry is undergoing a major transition.
CFC refrigerants such as R-11 and R-12 have been phased out because they damage the ozone layer. HCFC refrigerants such as R-22 are also being phased out. High-GWP HFC refrigerants are not universally prohibited, but their consumption is being reduced under the Kigali Amendment and many jurisdictions are introducing additional restrictions.
At the same time, refrigerants such as ammonia (R-717), carbon dioxide (R-744), propane (R-290), R-32, HFOs and selected low-GWP blends are playing increasingly important roles in modern refrigeration and air-conditioning technology.
There is therefore no single refrigerant that should simply be labelled “the world’s fully accepted refrigerant.” The correct choice depends on the application, equipment design, safety requirements, environmental characteristics, technical requirements and regulations applicable in the country where the equipment will operate.
For a new refrigeration installation, the objective should be to select a technically suitable, safe, energy-efficient and future-oriented refrigerant rather than simply choosing the refrigerant that is most familiar or cheapest today.
Akpo Oyegwa Refrigeration Company provides refrigeration engineering and cooling solutions for commercial and industrial applications, including cold rooms, blast freezers, cold storage systems and refrigeration equipment. Refrigerant selection should always be based on the specific system design and application requirements.
Disclaimer: Refrigerant regulations change over time and may differ between countries and applications. This article provides general technical information and should not be treated as a substitute for checking the current regulations applicable to a specific project.
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