The History of Refrigerants: From Freon to Eco-Friendly Gas

If you’ve ever had a technician tell you that your AC unit uses R-22 and replacement refrigerant is expensive — or that your new system runs on R-410A or R-454B — you’ve encountered the long, complicated history of refrigerants firsthand. What gets pumped through your AC system has changed dramatically over the last century, driven by a combination of engineering breakthroughs, environmental crises, and evolving federal regulation. Understanding that history helps every business owner and homeowner in Arizona make smarter decisions about their cooling equipment.

At Discount AC & Refrigeration, our licensed technicians work with every generation of refrigerant — from legacy R-22 systems still running in older commercial buildings to the latest low-GWP blends now required in new installations. This guide traces the history of refrigerants from early toxic compounds to today’s eco-friendly gases, and explains what it means for HVAC equipment in the Phoenix East Valley.

The History of Refrigerants Begins Before Freon

Before synthetic refrigerants existed, the mechanical refrigeration industry relied on substances that worked — but came with serious risks. The earliest commercial refrigerants, used from the 1830s through the early 1900s, included:

• Ammonia (NH₃) — Highly efficient, still used in large industrial refrigeration today, but toxic and corrosive at leak concentrations above 25 ppm.
• Sulfur dioxide (SO₂) — Used in domestic refrigerators through the 1920s; a severe respiratory irritant at any leak level.
• Methyl chloride (CH₃Cl) — Flammable and toxic; responsible for multiple fatal accidents in residential settings.
• Carbon dioxide (CO₂) — Non-toxic but required extremely high operating pressures; largely phased out of residential use by mid-century.

The danger profile of these early refrigerants created real public health incidents. A methyl chloride leak in a hospital refrigerator in Cleveland in 1929 killed more than 100 people — and directly motivated the search for a safer alternative.

The Freon Era: CFCs and the Rise of R-12

In 1930, chemists at General Motors and DuPont introduced dichlorodifluoromethane — marketed as Freon-12, or R-12 — the first of the chlorofluorocarbon (CFC) refrigerant family. R-12 was non-toxic, non-flammable, chemically stable, and effective across a wide range of temperatures. It became the dominant refrigerant for automotive AC, household refrigerators, and light commercial cooling almost immediately.

Through the 1940s, 1950s, and 1960s, the history of refrigerants is largely the history of CFCs expanding into every corner of commercial and residential cooling. R-11, R-12, R-113, R-114, and related compounds became the backbone of the global refrigeration industry. In Phoenix, where air conditioning shifted from luxury to survival necessity in the post-WWII boom, R-12 systems cooled homes, restaurants, supermarkets, and office buildings across the rapidly growing East Valley.

For decades, no one worried about what happened when CFC refrigerants leaked into the atmosphere. They were considered essentially inert.

The Environmental Crisis: CFCs and the Ozone Layer

In 1974, chemists Mario Molina and F. Sherwood Rowland published research demonstrating that CFC molecules, after migrating to the stratosphere, were broken apart by UV radiation — releasing chlorine atoms that catalytically destroyed ozone molecules. One chlorine atom could destroy tens of thousands of ozone molecules before being deactivated.

By the early 1980s, satellite data confirmed a massive “ozone hole” forming over Antarctica every spring. The ozone layer absorbs ultraviolet-B radiation; its depletion was directly linked to increased rates of skin cancer, cataracts, and crop damage globally.

The international response was swift by regulatory standards. The Montreal Protocol, signed in 1987 and ratified by every UN member nation, mandated the global phaseout of ozone-depleting substances including all CFC refrigerants. In the United States, the Clean Air Act of 1990 and EPA regulations under Section 608 formalized the phaseout timeline, banned intentional venting of refrigerants, and established the certification requirements that licensed HVAC technicians — including our team at Discount AC & Refrigeration — must hold today.

R-12 was officially banned for new equipment in the U.S. starting in 1994. The phase down of existing R-12 supply continued through the 1990s until recycled stocks became the only legal source.

The HCFC Bridge: R-22 and Its Own Phaseout

To replace CFCs, the industry turned to hydrochlorofluorocarbons (HCFCs) — compounds that retained some chlorine but included hydrogen atoms that caused them to break down in the lower atmosphere before reaching the stratosphere. They were far less damaging to the ozone layer than CFCs, though not entirely benign.

R-22 (chlorodifluoromethane) became the dominant HCFC refrigerant for residential and light commercial air conditioning from the mid-1990s through the 2000s. Millions of split systems, package units, and heat pumps across the U.S. — including a large portion of the aging commercial building stock in Phoenix — were designed around R-22.

But HCFCs were always intended as a transitional solution. The Montreal Protocol required their eventual phaseout as well. In the United States:

• 2010: New AC equipment using R-22 banned for manufacture and import.
• 2020: Production and import of R-22 banned entirely. Only recovered and recycled R-22 is now legally available.

The result: R-22 prices spiked dramatically after 2020. What once cost $5–10 per pound now frequently runs $50–100+ per pound for recovered stock, depending on availability. For Arizona homeowners and business owners still running R-22 systems — many of which are now 15–20+ years old — this is a direct cost driver pushing the repair-vs-replace decision strongly toward replacement.

Our licensed technicians help clients across the East Valley navigate exactly this calculation. If you’re running an older R-22 system and facing a refrigerant leak or compressor failure, understanding the full cost picture is critical. Visit our page on AC replacement cost estimates in Gilbert to understand what a modern system upgrade typically involves.

Refrigerant History at a Glance

The HFC Era: R-410A and the Climate Problem

With CFCs and HCFCs being phased out, the industry shifted to hydrofluorocarbons (HFCs) — compounds containing no chlorine, meaning zero ozone depletion potential. R-410A, a 50/50 blend of R-32 and R-125, became the industry standard for residential and commercial AC equipment from the late 1990s onward. It was more efficient than R-22, required higher operating pressures (leading to system redesigns), and was widely considered the long-term solution.

The problem: R-410A has a Global Warming Potential (GWP) of 2,088 — meaning a pound of R-410A released into the atmosphere traps 2,088 times more heat over 100 years than a pound of CO₂. HFCs don’t damage the ozone layer, but they are potent greenhouse gases. The Kigali Amendment to the Montreal Protocol (2016) and the U.S. AIM Act (American Innovation and Manufacturing Act, 2020) both mandate an 85% phasedown of HFC production by 2036.

The practical result for Arizona HVAC: new residential and light commercial equipment manufactured after January 1, 2025 must use refrigerants with a GWP below 700. R-410A no longer meets that threshold for new equipment.

Today’s Eco-Friendly Refrigerants: HFOs and Natural Options

The current generation of refrigerants — the ones going into new equipment rolling off production lines right now — falls into two main categories:

HFO Blends (Hydrofluoroolefins)

HFOs are a newer class of synthetic refrigerant with very low GWP values. The leading replacement for R-410A in new residential and commercial AC equipment is R-454B (marketed as Puron Advance by Carrier), with a GWP of 466. Other common options include R-32 (GWP 675) and R-452B. These refrigerants deliver comparable or better efficiency to R-410A but with roughly 75–80% lower climate impact.

One important note: most HFO blends are mildly flammable (classified A2L by ASHRAE), which requires specific installation and service protocols. Technicians need updated training, and equipment needs compliant installation per local codes — something our team at Discount AC & Refrigeration’s commercial HVAC division is fully equipped to handle.

Natural Refrigerants

Natural refrigerants have returned to prominence after a century-long detour through synthetic chemistry:

• R-290 (propane): GWP of just 3. Highly efficient, widely used in commercial refrigeration display cases, reach-in coolers, and vending equipment. Flammable, so charge sizes are limited, but modern equipment designs manage this safely. Many of the commercial refrigeration systems we service in restaurants and grocery operations are now transitioning to R-290.
• CO₂ (R-744): GWP of 1. Used in transcritical refrigeration systems for supermarkets and large commercial applications. Requires specialized high-pressure equipment but is becoming increasingly viable as the technology matures.
• Ammonia (R-717): Still the preferred refrigerant for large industrial cold storage and food processing facilities due to its exceptional efficiency. Requires strict safety protocols and certified systems.

What This History Means for Your Arizona HVAC System

The history of refrigerants isn’t just a chemistry lesson — it has direct, practical implications for every business owner and homeowner in the Phoenix East Valley:

If you have an R-22 system: Recovered R-22 is available but expensive and will only become more so as existing stocks deplete. Any significant refrigerant leak — or a compressor failure — almost certainly justifies full system replacement with a modern R-454B or R-32 unit. Our team can help you evaluate the exact cost trade-off. See our AC replacement cost estimates in Gilbert for current pricing context.

If you have an R-410A system: R-410A will remain serviceable for many years — existing equipment doesn’t need to be replaced, and recovered R-410A will be available. But if you’re facing a major repair on an older R-410A system, it may make economic and environmental sense to upgrade to a new high-efficiency unit now rather than investing in an aging platform.

If you’re buying new equipment: Any new system installed today uses R-454B or another low-GWP refrigerant. These systems are more efficient, better for the environment, and built to meet the regulations of the next 20+ years. In Arizona’s climate — where AC systems run 4–6 months a year at full load in 110–115°F heat — efficiency improvements translate directly to meaningful utility savings.

Our licensed HVAC technicians at Discount AC & Refrigeration hold the EPA Section 608 certification required for all refrigerant handling, and we stay current with the evolving regulatory landscape under the AIM Act. Whether you need service on a legacy R-22 system or installation of the latest eco-friendly equipment, we serve Gilbert, Mesa, Chandler, Tempe, Queen Creek, and the surrounding East Valley with honest, code-compliant work.

If you’re dealing with a refrigerant leak or an aging system that needs assessment, our team is available for 24/7 emergency AC repair as well as scheduled diagnostics. You can see why East Valley homeowners and businesses trust our team through our verified Google reviews.

The Right Refrigerant for Your System — Ask a Licensed Technician

A century of refrigerant development has brought us from toxic industrial gases to ozone-destroying CFCs to potent greenhouse gases — and finally to today’s low-GWP synthetic blends and natural refrigerants. Each transition has been driven by science, environmental necessity, and federal regulation. The next chapter is already written into the AIM Act phasedown schedule.

The most important thing you can do as a property owner is work with licensed, certified technicians who understand both the chemistry and the compliance requirements. Using the wrong refrigerant, improperly retrofitting an old system, or ignoring a leak doesn’t just void equipment warranties — it violates federal law under Section 608 and can result in significant fines.

Discount AC & Refrigeration holds Arizona ROC License 361623 and our entire service team is EPA Section 608 certified. We’re available 6 AM to Midnight, 7 days a week across the Phoenix East Valley. Call (480) 478-2616 to schedule a refrigerant inspection, system diagnostic, or equipment replacement consultation. Or contact us online — and check out our Refer & Earn program if you know someone else who could use our services.