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R-410A, sold under the trademarked names AZ-20, EcoFluor R410, Forane 410A, Genetron R410A, Puron, and Suva 410A, is a zeotropic but near-azeotropic mixture of difluoromethane (CH2F2, called R-32) and pentafluoroethane (CHF2CF3, called R-125) that is used as a refrigerant in air conditioning and heat pump applications. R-410A cylinders were colored rose but are no longer specially color-coded, now bearing a standard light gray color.[1][2]

On December 27, 2020, the United States Congress passed the American Innovation and Manufacturing (AIM) Act, which directs US Environmental Protection Agency (EPA) to phase down production and consumption of hydrofluorocarbons (HFCs).[3] HFCs have a high global warming potential and contribute to climate change. Rules developed under the AIM Act require HFC production and consumption to be reduced by 85% from 2022 to 2036.[4] R-410A will be restricted by this Act because it contains the HFC R-125. Other refrigerants (like R-32 and R-454B)[5] will replace R-410A in most applications, just as R-410A replaced the earlier refrigerant, R-22.


R-410A was invented and patented by Allied Signal (now Honeywell) in 1991.[6] Other producers around the world have been licensed to manufacture and sell R-410A, but Honeywell continues to be the leader in capacity and sales.[7] R-410A was successfully commercialized in the air conditioning segment by a combined effort of Carrier Corporation, Emerson Climate Technologies, Inc., Copeland Scroll Compressors (a division of Emerson Electric Company), and Allied Signal. Carrier Corporation was the first company to introduce an R-410A-based residential air conditioning unit into the market in 1996 and holds the trademark "Puron".[8][9]

Transition from R-22 to R-410A[edit]

R-410A replaced R-22 as the preferred refrigerant for use in residential and commercial air conditioners in Japan, Europe, and the United States.[10][failed verification]

Parts designed specifically for R-410A must be used, as R-410A operates at higher pressures than other refrigerants. R-410A systems thus require service personnel to use different tools, equipment, safety standards, and techniques. Equipment manufacturers are aware of these changes and require the certification of professionals installing R-410A systems. In addition, the AC&R Safety Coalition has been created to help educate professionals about R-410A systems.

R-22 Phaseout[edit]

In accordance with terms and agreement reached in the Montreal Protocol (The Montreal Protocol on Substances That Deplete the Ozone Layer), the United States Environmental Protection Agency has mandated that production or import of R-22 along with other hydrochlorofluorocarbons (HCFCs) be phased out in the United States. In the EU and the US, R-22 cannot be used in the manufacture of new air conditioning or similar units from 1 January 2010.[10] In other parts of the world, the phase-out date varies from country to country. All newly manufactured window air conditioners and mini split air conditioners in the United States come with R-410A.[11] Since 1 January 2020, the production and importation of R-22 has been banned; the only available sources of R-22 include that which has been stockpiled or recovered from existing devices.[10]

R-410A use expanded globally and rapidly as it replaced R-22.[12]

Environmental effects[edit]

Rapid growth of R-410A (HFC-125/HFC-32) atmospheric concentrations (bottom-right graph).

Unlike alkyl halide refrigerants that contain bromine or chlorine, R-410A (which contains only fluorine) does not contribute to ozone depletion and is therefore becoming more widely used as ozone-depleting refrigerants like R-22 are phased out. However, like methane, its global warming potential (GWP) is appreciably worse than CO2 for the time it persists. Because R410A is a 50% combination of CH2F2 (HFC-32) and 50% CHF2CF3 (HFC-125), it is not easy to express their combined effects in a single global warming potential (GWP),[13][14] However, HFC-32 has a 4.9 year lifetime and a 100-year GWP of 675 and HFC-125 has a 29-year lifetime and a 100-year GWP of 3500.[13] The combination has a GWP of 2088, higher than that of R-22 (100-year GWP=1810), and an atmospheric lifetime of nearly 30 years compared with the 12-year lifetime of R-22.[15][16]

Since R-410A allows for higher SEER ratings than an R-22 system by reducing power consumption, the overall impact on global warming of R-410A systems can, in some cases, be lower than that of R-22 systems due to reduced greenhouse gas emissions from power plants.[14] This assumes that the atmospheric leakage will be sufficiently managed.[17] Under the assumption that preventing ozone depletion is more important in the short term than GWP reduction, R-410A is preferable to R-22.[14]

R-410A Phaseout[edit]

The phase-down mandated by the AIM Act will lead to R-410A's replacement by other refrigerants beginning in 2022. Alternative refrigerants are available, including hydrofluoroolefins, hydrocarbons (such as propane R-290 and isobutane R-600A), and even carbon dioxide (R-744, GWP = 1).[18][19] The alternative refrigerants have much lower GWP than R-410A.

Physical properties[edit]

Physical properties of R-410A refrigerant[20][21][22]
Property Value
CH2F2 (difluoromethane) (50%)
CHF2CF3 (pentafluoroethane) (50%)
Molecular weight (Da) 72.6
Melting point (°C) −155
Boiling point (°C) −48.5
Liquid density (30 °C), kg/m3 1040
Vapour density (30 °C), air=1.0 3.0
Vapour pressure at 21.1 °C (MPa) 1.383
Critical temperature (°C) 72.8
Critical pressure, MPa 4.90
Gas heat capacity (kJ/(kg·°C)) 0.84
Liquid heat capacity @ 1 atm, 30 °C, (kJ/(kg·°C)) 1.8
Flash point R-410A should not be mixed with air (oxygen) under pressure
Autoignition temperature Difluoromethane: 648 °C; pentafluoroethane is fire-retardant

Thermophysical properties - Properties of refrigerant R410a


R-410A cannot be used in R-22 service equipment because of higher operating pressures (approximately 40 to 70% higher).

While R-410A has negligible fractionation potential, it cannot be ignored when charging.

Trade names[edit]

  • Suva 410A (DuPont)
  • Puron (Carrier)
  • Genetron AZ-20 (Honeywell)

See also[edit]


  1. ^ "Refrigerants - Color Codes". www.engineeringtoolbox.com.
  2. ^ "Refrigerant Color Codes". 24 May 2023.
  3. ^ "Protecting Our Climate by Reducing Use of HFCs". US Environmental Protection Agency. 8 February 2021. Retrieved 25 August 2022.
  4. ^ EPA Press Office (23 September 2021). "U.S. Will Dramatically Cut Climate-Damaging Greenhouse Gases with New Program Aimed at Chemicals Used in Air Conditioning, Refrigeration". US Environmental Protection Agency. Retrieved 25 August 2022.
  5. ^ Johnston, Philip (2020-10-13). "What's Next: Specifying the Right R-410A Replacement". Engineered Systems Magazine.
  6. ^ "Home". www.honeywell.com. Archived from the original on November 16, 2007.
  7. ^ "Home". www.honeywell.com. Archived from the original on November 25, 2007.
  8. ^ "PURON - Reviews & Brand Information - Carrier Corporation SYRACUSE, NY - Serial Number: 77215886". Trademarkia.com. Retrieved 2016-05-01.
  9. ^ "Refrigerants". Carrier Corporation. Archived from the original on 31 March 2012.
  10. ^ a b c "EPA R-22 Phase-out". Archived from the original on 2016-01-17. Retrieved 2011-07-07.
  11. ^ "Honeywell AZ-20 (R-410A) Refrigerant". Archived from the original on 2017-09-24. Retrieved 2021-09-01.
  12. ^ "Global R410A Market 2020 Growth Analysis...Showing Impressive Growth by 2026". marketwatch.com. 2020-08-15.[permanent dead link]
  13. ^ a b Velders, Guus J. M.; Fahey, David W.; Daniel, John S.; McFarland, Mack; Andersen, Stephen O. (July 7, 2009). "The large contribution of projected HFC emissions to future climate forcing". Proceedings of the National Academy of Sciences. 106 (27): 10949–10954. Bibcode:2009PNAS..10610949V. doi:10.1073/pnas.0902817106. PMC 2700150. PMID 19549868.
  14. ^ a b c Pierrehumbert, R.T. (May 30, 2014). "Short-Lived Climate Pollution". Annual Review of Earth and Planetary Sciences. 42 (1): 341–379. Bibcode:2014AREPS..42..341P. doi:10.1146/annurev-earth-060313-054843.
  15. ^ "IPCC Assessment Report 4 (AR4) 2007" (PDF). p. 212. Retrieved 25 August 2022.
  16. ^ "High-GWP Refrigerants". California Air Resources Board. Retrieved 25 August 2022.
  17. ^ "The Essentials Of Working With R-410A" (PDF). Florida State College at Jacksonville. p. 7. Archived from the original (PDF) on September 4, 2014. Retrieved November 21, 2013.
  18. ^ "Choosing a New System?". California Air Resources Board. Retrieved 25 August 2022.
  19. ^ "TRANSITIONING TO LOW-GWP ALTERNATIVES in Residential and Commercial Air Conditioning and Chillers" (PDF). US Environmental Protection Agency. December 2016. Retrieved 25 August 2022.
  20. ^ "R-410a Material Safety Data Sheet" (PDF). Honeywell International Inc. Archived from the original (PDF) on 2010-10-11. Retrieved 2009-07-03.
  21. ^ "Puron Refrigerant R-410A" (PDF). Archived from the original on 21 December 2006. Retrieved 2 July 2014.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  22. ^ "R-410A" (PDF). Honeywell Refrigerants Europe. Archived from the original (PDF) on 27 March 2014. Retrieved 26 April 2013.