Refrigerant Types Guide: R-22, R-410A, R-32, R-454B & More

Last updated: 2026  ·  Covers EPA AIM Act regulations & current phase-down schedule

If you work in HVAC and refrigeration, you already know that the refrigerant landscape has changed dramatically over the past decade — and it’s still changing. The phase-out of R-22, the ongoing phase-down of R-410A, and the rise of low-GWP alternatives like R-454B and R-32 have left many technicians, contractors, and facility managers scrambling to keep up with which refrigerants are legal, which are being discontinued, and which to specify for new equipment.

This refrigerant types comparison guide cuts through the confusion. We cover every major refrigerant in commercial use today — from legacy HCFCs to natural refrigerants — including their properties, applications, safety classifications, environmental impact, and current regulatory status under the EPA’s AIM Act. Whether you’re servicing existing equipment or specifying new systems, this is your reference.

How Refrigerants Are Classified

Before diving into specific refrigerants, it helps to understand the classification system. Refrigerants are grouped by their chemical composition and by their safety profile.

By Chemical Family

• CFCs (Chlorofluorocarbons): Oldest class; extremely high ozone depletion potential (ODP). Fully phased out globally under the Montreal Protocol. Examples: R-11, R-12.
• HCFCs (Hydrochlorofluorocarbons): Transitional replacement for CFCs; lower ODP but still ozone-depleting. R-22 is the most well-known. Phased out in the US for new equipment since 2010; production ended January 1, 2020.
• HFCs (Hydrofluorocarbons): No ODP, but high global warming potential (GWP). Currently the most widely used class. R-410A, R-134a, and R-404A are HFCs. Being phased down under the AIM Act.
• HFOs (Hydrofluoroolefins): Next-generation synthetic refrigerants with very low GWP. Often blended with HFCs as transition refrigerants. Examples: R-1234yf, R-454B, R-32 (technically an HFC but low GWP).
• Natural Refrigerants: CO₂ (R-744), Ammonia (R-717), Propane (R-290), and Isobutane (R-600a). Ultra-low or zero GWP and ODP. Trade-offs include higher operating pressures, toxicity, or flammability.

By Safety Classification (ASHRAE 34)

All refrigerants are assigned an ASHRAE 34 safety classification based on toxicity (A = lower, B = higher) and flammability (1 = none, 2L = mildly flammable, 2 = flammable, 3 = highly flammable). Understanding this is critical for safe system design and service.

Legacy Refrigerants: What You Need to Know

R-22 (HCFC-22) — Phased Out

Status: BANNED for new equipment and new production since January 1, 2020. Recovered and reclaimed R-22 is still legal for servicing existing equipment but supplies are shrinking and prices are high.

R-22 was the dominant refrigerant for residential and light commercial air conditioning for decades. It operates at moderate pressures, has good thermodynamic properties, and is compatible with mineral oil. However, its ODP of 0.055 made it a target under the Montreal Protocol.

If you’re servicing an R-22 system today, your options are: continue using reclaimed R-22 (increasingly expensive), retrofit to an approved alternative like R-407C or R-421A, or recommend full system replacement. For equipment over 10-15 years old, replacement is almost always the more cost-effective long-term path.

R-134a (HFC-134a) — Transitioning

Status: Still in use but subject to HFC phase-down under the AIM Act. Being replaced by R-1234yf in automotive applications and R-513A or R-450A in medium-temperature commercial refrigeration.

R-134a was introduced as the primary CFC-12 replacement and became the standard refrigerant for automotive air conditioning and medium-temperature commercial refrigeration (display cases, beverage coolers). It is non-flammable (A1), chemically stable, and compatible with POE oil. With a GWP of 1,430 it is now considered a high-GWP refrigerant subject to phase-down.

R-404A — High GWP, Actively Transitioning

Status: Still operational in existing equipment but the highest GWP of any commonly used commercial refrigerant at 3,922. Many manufacturers no longer offer new equipment designed for R-404A.

R-404A became the workhorse of low-temperature commercial refrigeration — supermarket freezer cases, cold storage, ice machines, and transport refrigeration. Its high GWP has made it a priority target for phase-down. Common retrofit alternatives include R-448A, R-449A, and R-452A, which are drop-in compatible with most R-404A equipment after a refrigerant flush and filter-drier replacement.

Current Transition Refrigerants

R-410A — The Standard Being Replaced

Status: New residential AC equipment using R-410A was banned starting January 1, 2025 under EPA AIM Act rules. Existing systems will continue to be serviced with R-410A for years to come.

R-410A dominated residential and light commercial air conditioning for nearly 30 years. It operates at approximately 60% higher pressure than R-22, requires POE oil, and delivers excellent energy efficiency. Its GWP of 2,088 triggered phase-down regulations, and the industry has moved to R-454B and R-32 for new equipment.

For service technicians: the installed base of R-410A equipment is enormous and will require service for the next 15-20 years. R-410A refrigerant will remain available for servicing existing equipment through the transition period, but expect prices to rise as production scales back.

R-32 — The Mid-GWP Transition Option

Status: Approved and in active use. Common in mini-split systems from major manufacturers including Daikin, Mitsubishi, and others. Classified A2L (mildly flammable).

R-32 has a GWP of 675 — about one-third that of R-410A — and delivers slightly higher efficiency in many applications. Its primary trade-off is its A2L mildly flammable classification, which requires updated installation practices and compatible equipment design. Many newer mini-split and VRF systems are designed specifically for R-32.

R-32 is a single-component refrigerant, which means it can be recovered and recharged without the fractionation concerns associated with blends. This simplifies service in the field.

R-454B (Opteon XL41) — The Primary R-410A Successor

Status: Approved by the EPA as the preferred replacement for R-410A in new residential and commercial AC equipment. Major manufacturers including Carrier, Trane, Lennox, and York have transitioned new product lines to R-454B.

R-454B is an HFO/HFC blend with a GWP of 466 — about 78% lower than R-410A. It operates at similar pressures to R-410A, making it relatively compatible with existing system designs, though not a direct drop-in replacement. Equipment must be designed for R-454B.

Like R-32, R-454B carries an A2L classification. Installers working with A2L refrigerants need to be aware of leak detection requirements, equipment room ventilation, and proper handling procedures. ASHRAE 15 and local codes govern these requirements.

R-448A and R-449A — R-404A Retrofits

Status: Approved retrofit refrigerants designed to replace R-404A and R-507 in existing commercial refrigeration equipment. Lower GWP than R-404A with minimal system modifications required.

These HFO/HFC blends are designed to be relatively drop-in replacements for R-404A in medium and low-temperature commercial refrigeration. They typically require a refrigerant flush, new filter-drier, possible oil change to POE, and expansion valve adjustment. Consult the equipment manufacturer before any retrofit.

Natural Refrigerants: The Long-Term Future

Natural refrigerants have existed since the earliest days of refrigeration. They are experiencing a global resurgence driven by regulatory pressure on synthetic refrigerants and advances in system design that make them practical for commercial applications.

R-744 (CO₂) — The Supermarket Standard

Status: Rapidly growing adoption in commercial refrigeration, particularly in supermarkets and cold chain logistics. GWP of 1. No ODP. Excellent long-term regulatory outlook.

CO₂ refrigeration systems — particularly transcritical CO₂ rack systems — are now the dominant technology in new European supermarket construction and are gaining rapid ground in North America. CO₂ operates at much higher pressures than HFC refrigerants (up to 1,500 psi in transcritical operation), which requires purpose-built equipment, components, and trained technicians.

The efficiency of transcritical CO₂ is highly climate-dependent. In colder climates, CO₂ systems outperform HFC equivalents. In hotter climates, efficiency can suffer without supplemental sub-cooling technologies like adiabatic gas coolers or mechanical sub-cooling. These challenges are increasingly addressed by hybrid configurations.

R-717 (Ammonia, NH₃) — The Industrial Workhorse

Status: The refrigerant of choice for large industrial refrigeration: cold storage warehouses, food processing, ice rinks, and industrial process cooling. GWP of 0. ODP of 0.

Ammonia has the best thermodynamic efficiency of any common refrigerant — a COP often 10-20% higher than equivalent HFC systems. It is also inexpensive, widely available, and leaves no residual environmental impact. Its trade-offs are significant: ammonia is toxic (IDLH: 300 ppm), requires specialized leak detection, secondary loop systems in occupied spaces, and compliance with OSHA PSM and EPA RMP regulations above threshold quantities.

Ammonia is NOT appropriate for small commercial applications. It is an industrial refrigerant requiring purpose-built systems, certified operators, and rigorous safety programs.

R-290 (Propane) and R-600a (Isobutane) — Small Commercial Naturals

Status: Approved for use in small, self-contained commercial equipment with charge limits. GWP of 3. Growing adoption in plug-in display cases, vending machines, and domestic refrigerators.

Propane and isobutane deliver excellent thermodynamic performance and ultra-low environmental impact. Their A3 (highly flammable) classification limits charge sizes under current US regulations — typically to 150g or less per circuit in commercial applications. They are well-suited to hermetically sealed, factory-built equipment where charge containment is assured by design.

Master Refrigerant Comparison Table (2025)

The Regulatory Timeline: AIM Act & EPA Phase-Down

The American Innovation and Manufacturing (AIM) Act, signed in 2020, gives the EPA authority to phase down HFC production and consumption in the United States. The phase-down follows a stepwise schedule:

• 2022: HFC production/import capped at 90% of baseline.
• 2024: Cap reduced to 60% of baseline.
• 2029: Cap reduced to 30% of baseline.
• 2034: Cap reduced to 20% of baseline.
• 2036: Long-term stabilization at 15% of baseline.

Separately, EPA technology transition rules have set equipment-level deadlines. New residential and light commercial AC equipment cannot use R-410A as of January 1, 2025. New commercial refrigeration equipment must use lower-GWP refrigerants on a phased schedule by application category.

How to Choose the Right Refrigerant

With so many options, selecting the right refrigerant comes down to four key questions:

• New equipment or retrofit? New equipment should always use the manufacturer-specified refrigerant — never substitute. For retrofits, consult manufacturer retrofit guides and consider charge compatibility, oil type, and expansion valve adjustment.
• What is the application temperature? High-temperature AC applications favor R-454B or R-32. Medium-temperature commercial refrigeration typically uses R-448A, R-449A, or R-134a replacements. Low-temperature freezer applications often use R-448A, R-449A, or CO₂ in large systems.
• What are the safety constraints? A2L refrigerants require compliant equipment and updated installation practices. A3 refrigerants (propane, isobutane) are limited to factory-sealed equipment with small charges. Ammonia is restricted to industrial applications with full safety programs.
• What is the long-term regulatory outlook? Prioritize refrigerants with GWP below 750 for any new equipment or major retrofit. This ensures the system remains compliant through foreseeable future regulations.

Conclusion

The refrigerant transition is not a single event — it is an ongoing shift that will continue to reshape the HVAC and commercial refrigeration industry through the 2030s and beyond. R-22 is gone. R-410A is on its way out for new equipment. R-454B and R-32 are taking over residential and commercial AC. Natural refrigerants — CO₂, ammonia, and hydrocarbons — are the long-term future for commercial refrigeration at scale.

For technicians and contractors, staying current on refrigerant regulations is not optional — it is a legal and professional requirement. EPA Section 608 certification, proper recovery procedures, and up-to-date knowledge of approved refrigerants protect your business and your customers.

Bookmark this guide and check back annually — we update it to reflect the latest EPA regulatory developments and equipment transitions.

George Service field manager

George Stahov is an HVAC engineer with over 12 years of experience in heating, cooling, and refrigeration. As the owner of Four Elements Service, he specializes in high-efficiency system design, diagnostics, and installation. Recognized with professional awards from Carrier and Mitsubishi, George provides trusted, expert insights for homeowners and businesses.

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George Stahov