top of page

Preparing for the Future of HVAC

The End of R-410A and the Rise of Environmentally-Friendly Refrigerants

Refrigeration Cycle

What are refrigerants?

Refrigerants are chemical substances that absorb and transfer heat as part of the refrigeration cycle. In air conditioning systems, refrigerants absorb heat from the warm air inside a building, and transfer it outside, which has a cooling effect on the inside space. As they pass through the cycle, refrigerants experience changes in state between liquid and gas due to the changes in pressure and temperature caused by the evaporator, compressor, condenser, and expansion valve.


The first modern day refrigerant discovered was R-12, led by engineer Thomas Midgley Jr. in 1925. Prior to this discovery, different chemical compounds such as ammonia and propane were used as refrigerants, which were highly toxic and flammable. R-12 became very popular and was used in cooling applications including home and car air conditioning and refrigerators for many years. It is a CFC, meaning it contains carbon, fluorine, and chlorine atoms. R-12 had a monopoly on the refrigeration industry until 1950, when a new refrigerant called R-22 started to overtake R-12 in home air conditioners and refrigerators. R-22 is a HCFC compound, meaning it has the same atomic makeup of R-12, but with the addition of Hydrogen. CFCs are bad for the environment and cause Ozone depletion, which was the main reason for the switch to R-22. While these HCFCs did not deplete the Ozone, they did still have a high potential for global warming, so researchers in the industry began looking elsewhere for their refrigerant needs.

In the late 1980’s, the United Nations signed a treaty called the Montreal Protocol to begin phasing out the use of CFCs in refrigeration, therefore making the original refrigerant R-12 defunct. While R-22 continued to be used in homes, cars made the switch to a new refrigerant compound called R-134A. This compound was considered an HFC, meaning it is made up atomically of Hydrogen, Fluorine and Carbon. Similar to R-22, this new refrigerant did not have the same negative effect on the Ozone, but still carried high global warming potential. It wasn’t until 2010 that the Environmental Protection Agency (EPA) stepped in and implemented a ban on the production and sale of R-22 and all other HCFCs that would take effect in 2020 due to their global warming potential.

With the high prevalence of R-22 in the HVAC industry, a new refrigerant was needed to take over the task of cooling homes. This refrigerant was R-410A, an HFC like R-134A that removed the presence of chlorine found in HCFCs. Today R-410A is the most popular refrigerant used in the United States. Since 2010, most cooling mechanical equipment has been designed specifically for the use of R-410A due to it having a higher pressure than previous refrigerants. This will soon be changing.

Present Day and Future:

The EPA recently declared a ban on high global warming potential HFCs that will take effect on January 1, 2024. This ban included R-410A and R-134A, the most common refrigerants found in homes and motor vehicles respectively. HVAC manufacturers are currently beginning to phase out R-410A utilized equipment in preparation for the incoming ban. This change will have a massive impact on the industry, and contractors will need to find a substitute to replace that hole left by this ban. One of the most popular alternatives currently is a refrigerant called R-454B. This compound is composed of 70% R-32, an HFC and 30% R-1234YF, an HFO. HFOs use the same atoms as an HFC: hydrogen, carbon, and fluorine, but they are composed in a different atomic structure. While HFO’s themselves are not good refrigerants, they provide no ozone depletion and low global warming potential, so when combined with an HFC it becomes an effective refrigerant with lower global warming potential. Popular manufacturers including Mitsubishi, Carrier and Trane have already identified R-454B as their new refrigerant of choice.

While on the surface R-454B seems like a good option due to its lack of environmental hazards, it is not without issues. Unlike previous mass manufactured refrigerants, R-454B is slightly flammable. Another manufacturer, Honeywell, has adapted the refrigerant R-466A which is nonflammable and has a global warming potential much lower then R-410A. Even with its lack of flammability, this refrigerant has not caught on in the industry as much due to its global warming potential not being quite as low as R-454B. The HVAC industry seems to have now targeted global warming potential as its most important refrigerant attribute, possibly in fear of another future ban that further lowers the global warming potential threshold. The transition from R-410A to R-454B won’t be an easy one, as equipment designed to use R-410 cannot shift to using R-454B due to their pressure and flammability differences. Buildings that currently utilize an R-410 air conditioner and wish to cause less environmental damage or need repairs on their existing equipment will need to purchase an entirely new piece of equipment that was designed to use R-454B. Only time will tell if R-454B can hold up long term as the new mainstream refrigerant in the industry.


Written by:

Tanner McCarthy, Mechanical Designer



  1. Johnson, A. (2021, November 10). What is refrigerant? Refrigerant HQ. Retrieved April 6, 2023, from

  2. Johnson, A. (2021, November 22). What is R-22 refrigerant? Refrigerant HQ. Retrieved April 6, 2023, from

  3. U.S. Department of State. (2021, January 5). The Montreal Protocol on substances that deplete the ozone layer - united states department of state. U.S. Department of State. Retrieved April 6, 2023, from,%2Ddepleting%20substances%20(ODS).

  4. US EPA confirms future restrictions on high-GWP refrigerants. HPT - Heat Pumping Technologies. (2016, December 9). Retrieved April 6, 2023, from,USA%20from%20January%201%2C%202024.


bottom of page