• Chemours Company technical fellow, Chuck Allgood.
    Chemours Company technical fellow, Chuck Allgood.

The Chemours Company technical fellow, Charles Allgood, explores key truths about today’s refrigerant options.

For more than a century, the world has used refrigerants for comfort, food preservation, manufacturing processes, and more. Many key products along the HVACR timeline remain with us in some capacity.

“Naturals”—hydrocarbons, sulfur dioxide, ammonia, and carbon dioxide (CO2)—were introduced over a century ago and are still used in some applications.

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs)—often categorized as Freon—find limited use in older equipment. Hydrofluorocarbons (HFCs), a popular solution that started in the late 1980s, still claim a significant part of the HVACR market. And in 2024, the industry is focusing heavily on new-generation hydrofluoroolefins (HFOs), a number of which are categorized as mildly flammable A2Ls.

Needless to say, the world has quite a number of refrigerant options today. To simplify things, CFCs and HCFCs— being phased out or phased down globally due to their ozone depletion potential (ODP)—can be removed from the equation.

HFCs are being phased down because of their higher global warming potential (GWP). This leaves “naturals” and zero-ODP HFOs which offer significantly lower GWPs.

Determining the best refrigerant option in terms of protecting the planet and performance is a hot topic these days.

Because in the broad scope of cooling applications worldwide, there is no single “magic solution” or definitive answer, it’s critical for individuals and businesses to make the most informed decision.

But the myths circulating today about HFOs and “naturals” can create a roadblock to decision-making. By clarifying these misconceptions, we establish solid ground for making appropriate choices for air conditioning and refrigeration equipment for upgrades or new installations.

Following are facts to replace predominant myths I’ve discovered through my interactions with everyone from HVACR shop owners and technicians to end users.

“Naturals” refrigerants aren’t actually natural.

It may sound logical that refrigerants marketed as “natural” are better for people and the planet. But like all refrigerants, these products are synthetic.

Refrigerant-grade products such as ammonia, propane, and other “naturals” are produced in industrial processes. Like HFOs, their production requires energy and feedstock consumption, purification, packaging, warehousing, and transport.

However, producing ammonia, for example, consumes a significant amount of energy and results in an enormous carbon footprint.

HFOs deliver on circularity, but many “naturals” do not.

HFOs, unlike many “naturals,” are recovered, reclaimed, and reused—supporting maximum resource efficiency, minimal waste, and lower emissions. HFOs are critical to advancing circularity across the many industries they touch and create a path to decarbonization.

Next-generation A2Ls have a very low GWP.

Chemists developed HFOs to address the high GWP of HFCs. Further innovation included the development of HFO blends allowing optimization that meets diverse performance, cost, safety, and sustainability needs of the entire industry.

Consider R-1234yf, an A2L component in many HFO and A2L blends. R-1234yf has an atmospheric lifetime of 11 days and a GWP of <1. R-454C, an A2L blend, has a GWP of <150.

Hydrocarbons are much more flammable than A2Ls.

A2Ls are mildly flammable compared with highly flammable (A3) hydrocarbons. Lower-flammability A2Ls that are commercially available and OEM-approved are about four times less likely to form flammable concentrations during an accidental leak than A3 alternatives such as propane and butane.

Moreover, systems using A2Ls are manufactured with leak detectors. Commonly used HFO blends are also more difficult to ignite. To demonstrate:

  • A2Ls—mild flammability and slow flame propagation (burning velocity of <10 cm/sec.)
  • A3s—higher flammability and faster flame propagation (burning velocity of >10 cm/sec.)

HFOs are reliable, have undergone rigorous regulatory approval processes, and are considered safe for their intended uses.

HFOs are more readily available than “naturals.”

With a strong and reliable supply chain, HFO refrigerants are positioned to support today’s numerous HVACR applications as well as the global A2L transition. In addition, there’s a much heartier pool of technicians trained to service HFO systems than there is for “naturals”—a critical need, given current workforce shortages.

HFOs can meet the industry’s diverse application requirements.

The HVACR industry has become highly complex and taken on an untold number of applications, each requiring unique refrigerant properties.

Although “natural” refrigerants—first adopted more than 100 years ago—can meet some of the demand, they have been broadly abandoned due to industry innovation and concerns over safety, energy consumption, and other factors. But HFOs are born in chemistry and its adaptability, so they enable safe, working environments.

HFOs also offer a strong global supply and a greater capability to meet changing needs driven by continual innovations in HVACR equipment and global sustainability requirements.

“Natural” and new-generation refrigerants have coexisted for some time, each serving specific HVACR needs. However, HFOs and A2Ls sit at the intersection of performance and sustainability, offering critical solutions for decarbonization, circularity, safety, and a business’s bottom line.

The need for new or updated AC or refrigeration systems offers an opportunity to make an informed decision that best supports corporate goals and the environment.

About the Author

Charles “Dr. Chuck” Allgood holds a PhD in chemistry, has more than 30 years of experience in the HVACR industry, and is a respected speaker at many industry events. In addition to Chemours, he’s worked for the National Institute of Standards and Technology.

Dr. Allgood has held a variety of research, development, business, technical service, training, and applications development positions with Chemours.

Most recently, he has focused on the development of low-GWP refrigerants—including Chemours Opteon brand refrigerants—and educating industry professionals about the changing regulatory landscape and A2L refrigerants on the market.