Refrigerant Types

The refrigerant in a system decides which tools you use, which oil goes in, what pressures to expect and which rules apply. Refrigerants have changed several times, and they are changing again. A working tech can meet R-22 from the 1990s, R-410A from the 2010s and R-454B from this year, all on the same street.

What You Will Be Able to Do

• Sort common refrigerants into their chemical families.
• Explain what ODP and GWP measure.
• Read an ASHRAE safety group such as A1 or A2L.
• Explain why refrigerants must never be mixed.
• Describe how the HFC phasedown affects new equipment and existing service work.

The Refrigerant Families

R-32 is a pure HFC, and R-454B is a blend of R-32 and an HFO. Both replace R-410A in many new home systems.

Measuring Environmental Harm

ODP (ozone depletion potential) rates how much a substance damages the ozone layer, compared with R-11 at 1.0. Chlorine does the damage, which is why CFCs and HCFCs were phased out. R-22 has an ODP of about 0.055. HFCs and HFOs have an ODP of zero because they contain no chlorine.

GWP (global warming potential) rates how much heat a gas traps in the atmosphere over 100 years, compared with carbon dioxide at 1.

ASHRAE Safety Groups

Each refrigerant carries a safety group with a letter and a number.

• A means lower toxicity, and B means higher toxicity.
• 1 means no flame spread, 2L means lower flammability, 2 means flammable and 3 means highly flammable.

So R-410A is A1. R-32 and R-454B are A2L. Ammonia (R-717) is B2L, and propane (R-290) is A3. Never treat an A2L or A3 system the way you treat an A1 system.

Oils

Oil must match the refrigerant so that it mixes and returns to the compressor. Older CFC and HCFC systems usually use mineral oil. HFC systems usually use polyolester oil (POE), and some use polyvinyl ether (PVE). POE absorbs water quickly from the air, so keep it capped and keep open system time short.

Blends and Why They Behave Differently

Many refrigerants are mixtures. Three terms matter:

• Azeotrope: the blend acts like one pure fluid. It boils at one temperature.
• Near-azeotrope: the blend has so little temperature change that it almost acts like one fluid. R-410A and R-404A fit here.
• Zeotrope: the blend boils across a range of temperatures, called glide. R-407C is an example.

Blends with glide can fractionate, meaning the parts separate. A leak can carry off more of one part than another. Vapor drawn from a cylinder can do the same. That is why blends are charged as liquid.

Why Refrigerants Are Never Mixed

Refrigerants that are mixed in a system or cylinder no longer match any pressure-temperature chart, so you cannot read them. Mixed refrigerants can damage the system, the oil can break down and form harmful acids, and a contaminated cylinder may be rejected or may cost extra to process. There is also no true drop-in replacement for an existing refrigerant. A replacement needs a check of oil, metering, seals and pressure ratings.

The AIM Act and the HFC Phasedown

The American Innovation and Manufacturing Act of 2020 directs EPA to cut U.S. HFC production and consumption by 85% by 2036, measured against a baseline. The steps are 40% from 2024, 70% from 2029, 80% from 2034 and 85% from 2036. HFCs are not banned. The supply is simply shrinking, so expect prices and availability to change.

What Changed for New Equipment

EPA's Technology Transitions rules limit the GWP of refrigerant used in new equipment. Key points, as of late 2026:

• New residential and light commercial AC and heat pumps must use refrigerant with a GWP of 700 or less. This applied to manufacture and import starting January 1, 2025. R-410A, at about 2,088, does not qualify. R-32 and R-454B do.
• A final rule published May 26, 2026 and effective July 27, 2026 removed the old January 1, 2026 installation deadline for R-410A split systems where every specified component was made or imported before January 1, 2025. That stock can still be installed until it runs out.
• Some states set their own dates, and a state rule can be stricter than the federal one.
• Variable refrigerant flow systems, chillers, cold storage and retail food refrigeration have their own limits and dates. Several retail and cold storage limits step down to 150 or 300 GWP in 2032, depending on charge size.

What This Means for Service

Existing equipment can keep running and keep being repaired, with the refrigerant it was built for. You do not have to replace an R-410A system because of its refrigerant.

Starting January 1, 2029, servicing supermarket systems, refrigerated transport and automatic commercial ice makers must use reclaimed HFC refrigerant. Reclaimed means it was processed back to purity by a certified reclaimer and contains no more than 15% virgin HFC by weight.

Warning: The rules in this area are changing quickly. Before you quote a date to a customer or order equipment, check the current EPA pages and your state rules.

Check Your Understanding

A customer asks whether their R-22 system is illegal to own. What is the correct answer? No. New R-22 production and import ended in 2020, but the system may still be used and serviced with recovered or reclaimed R-22.

A cylinder of recovered refrigerant contains two different refrigerants. Why is that a problem? Its pressure and temperature no longer match a chart, it cannot be reused in equipment, and a reclaimer may charge more or refuse it.

A new-construction job specifies a unit with a GWP of 2,088. Can a new unit of that kind be made in 2026? No. The new-manufacture limit for this equipment is 700 GWP.

What does A2L tell you? Lower toxicity and lower flammability. It can burn, so ignition sources must be controlled.

Key Takeaways

• CFCs and HCFCs contain chlorine and damage ozone. HFCs do not, but many trap a lot of heat.
• ODP compares ozone harm to R-11, and GWP compares warming to carbon dioxide.
• R-410A is A1, while R-32 and R-454B are A2L.
• Never mix refrigerants, and charge blends as liquid.
• The AIM Act cuts HFC supply 85% by 2036, and new home AC and heat pumps must stay at or below 700 GWP.
• Existing systems can still be serviced with the refrigerant they were designed for.