Refrigerant phaseouts explained: from Freon to R-410A to today’s new refrigerants

If you’ve shopped for an air conditioner recently, you’ve probably heard terms like R-22, R-410A, "phaseout" and "A2L." Here’s how we got here and what it means for the system in your home.

The early days: from dangerous to "safe"

Early refrigeration used chemicals like ammonia, sulfur dioxide and methyl chloride, which are toxic or flammable. In the late 1920s and 1930s, chlorofluorocarbons (CFCs) such as R-12, sold under the Freon brand, replaced them because they were stable, non-flammable and non-toxic. For decades, CFCs cooled cars, refrigerators and buildings.

The ozone problem and the Montreal Protocol

In 1974, scientists showed that CFCs drifting into the upper atmosphere were breaking down the ozone layer, which shields the earth from ultraviolet radiation. In 1985 researchers reported the "ozone hole" over Antarctica. In 1987, countries signed the Montreal Protocol to phase out ozone-depleting chemicals. In the U.S., the 1990 Clean Air Act Amendments put that into law, made it illegal to knowingly vent refrigerant, and created the EPA Section 608 certification that technicians need to handle refrigerant. U.S. production of CFCs ended at the end of 1995.

R-22: the long goodbye

Most home air conditioners from the 1970s through the 2000s used R-22, an HCFC. It does far less ozone damage than CFCs but still does some, so it was scheduled for phaseout too:

• 2010: new air conditioners and heat pumps could no longer be manufactured with R-22.
• January 1, 2020: production and import of R-22 ended in the U.S.
• Today: R-22 systems can still run and be serviced, but only with recovered, recycled or stockpiled refrigerant. That supply keeps shrinking, so R-22 repairs that need refrigerant are expensive.

R-410A, and why it’s being phased down

R-410A (often sold as "Puron") took over around 2010. It doesn’t harm the ozone layer, but it is a hydrofluorocarbon (HFC) with a high global warming potential (GWP), roughly 2,000 times that of carbon dioxide. In 2020, Congress passed the AIM Act, which phases down U.S. production and import of HFCs by 85% by 2036.

Under EPA rules that followed, new home air conditioners and heat pumps manufactured or imported from January 1, 2025 must use a refrigerant with a GWP of 700 or less, which rules out R-410A in new equipment. There was originally a January 1, 2026 deadline to install split systems built before 2025. In May 2026, the EPA removed that deadline, so contractors can keep installing R-410A equipment manufactured before 2025 until existing stock runs out.

The new refrigerants: R-454B and R-32

• Most new home systems now use R-454B (GWP around 466) or R-32 (GWP around 675).
• Both are classified "A2L," meaning lower toxicity and mildly flammable. Equipment is designed for that, often with built-in leak detection, and installers follow updated safety codes.
• R-454B ran short in 2025 as manufacturers switched over, which delayed some installations and raised prices.

What this means for you

• If your R-410A system works, you don’t need to replace it. R-410A remains available for servicing, though prices are expected to rise as supply is phased down.
• Refrigerants can’t be mixed or swapped. You can’t put R-454B into an R-410A system. Replacing equipment usually means the outdoor unit and indoor coil both need to match the new refrigerant.
• Be cautious of "drop-in" replacements for R-22 systems. Some are legal and workable, but they can affect performance and warranties. Ask the technician to explain the trade-offs in writing.
• A system that keeps needing refrigerant has a leak. Refrigerant isn’t used up like fuel, so a yearly "top-off" isn’t maintenance; finding and fixing the leak is.
• Only EPA Section 608 certified technicians should handle refrigerant.