Refrigerant GWP chart

What GWP means

Global warming potential (GWP) is the heat a gas traps over a set period compared with the same mass of carbon dioxide, which is 1 by definition. Refrigerant charts and US rules use the 100-year value. A GWP of 2,088 means one pound released traps as much heat over 100 years as 2,088 pounds of CO2.

GWP says nothing about ozone depletion, flammability or efficiency. R-22 has a lower GWP than R-410A but depletes ozone, which is why it was phased out under a different program (40 CFR 82). R-32 has a lower GWP than R-410A but is flammable (A2L).

AR4, AR5, AR6: why sites print different numbers

The IPCC has published GWP tables in several assessment reports, and each revision changes the values:

US regulation uses AR4. The exchange values in 40 CFR 84 Appendix A are the AR4 100-year GWPs: HFC-32 675, HFC-125 3,500, HFC-134a 1,430, HFC-143a 4,470, HFC-152a 124, HFC-23 14,800, HFC-227ea 3,220. Those are the numbers behind the AIM Act phasedown and the Technology Transitions limits.

For R-454B you will see 466 (AR4 with R-1234yf at 4, the common published value), 465 (EPA’s 40 CFR 84.64 calculation), 467 (AR5), 470 (EPA’s SNAP page, rounded) and 531 (AR6). All are correct for their basis. When two sources disagree, check the basis before assuming one is wrong. This site states AR4 everywhere and gives EPA’s value in a note where it differs.

How blend GWP is calculated

40 CFR 84.64 defines the method: the blend GWP is the sum of each constituent’s GWP multiplied by its nominal mass fraction.

• R-410A (50% R-32, 50% R-125): 0.50 × 675 + 0.50 × 3,500 = 2,087.5, published as 2,088.
• R-407C (23% R-32, 25% R-125, 52% R-134a): 0.23 × 675 + 0.25 × 3,500 + 0.52 × 1,430 = 1,773.9, published as 1,774.
• R-454B (68.9% R-32, 31.1% R-1234yf): with R-1234yf at 4, 465.1 + 1.2 = 466.3. With EPA’s value of 1, the result is 465.4.

The difference comes from the non-HFC constituents. AR4 has no value for HFOs or hydrocarbons, so 84.64 Table 1 assigns them: HFO-1234yf 1, HFO-1234ze(E) 1, HCFO-1233zd(E) 4, R-290 3.3, R-600 4, R-600a 1, R-717 1, R-744 1. Constituents with no listed value, such as HCFCs, CFCs and PFC-116, are left out of the sum (84.64(c)). That is why EPA’s figure for R-508B counts only its HFC-23 share and why R-401A comes out near 16 under 84.64.

The limits that use these numbers

The Technology Transitions rule (40 CFR 84.54) restricts new systems by GWP, sector by sector. For equipment a field tech meets most:

From 2032 the cold storage, remote condensing unit and supermarket limits are 150 for systems of 200 lb or more charge (other than the high side of a cascade), and 300 for systems under 200 lb and for the high side of cascades.

The May 2026 final rule (91 FR 31284, effective July 27 2026) lets new residential and light commercial split systems with GWP of 700 or more still be installed where all specified components were manufactured or imported before Jan 1 2025, with no end date. Servicing and repairing existing R-410A equipment remains legal. See the R-410A phase-out and the AIM Act rules for the full picture.

Two numbers sit close to the lines. R-32 (675) and R-513A (631) are under 700. R-449A (1,396.3 under 84.64) and R-448A (1,386.1) are under 1,400. EPA’s SNAP page rounds R-449A to 1,400, so use the 84.64 value when a limit is at stake.

Separately, the AIM Act phasedown caps HFC production and import on an exchange-value-weighted basis (40 CFR 84.7): 90% of baseline in 2022–2023, 60% in 2024–2028, 30% in 2029–2033, 20% in 2034–2035 and 15% from 2036. HFOs are not regulated substances under Part 84.

GWP chart: 62 refrigerants

Sorted from highest to lowest GWP. “GWP, AR4 basis” is the IPCC AR4 100-year value (mass-weighted for blends, with HFO constituents at the common industry values of 4 for R-1234yf and 6 for R-1234ze(E)). “EPA 40 CFR 84.64 value” is the figure EPA computes for Technology Transitions limits; a dash means the refrigerant has no Part 84 value. Safety classes are ASHRAE Standard 34.

Reading the chart

• Ozone-depleting refrigerants (R-11, R-12, R-113, R-22, R-123, R-502, R-500, R-401A, R-401B, R-408A, R-409A, R-416A) carry AR4 GWPs, but only their HFC share, if any, has a Part 84 value. They are controlled under 40 CFR 82, not the AIM Act.
• HFO, HCFO and natural refrigerants have no AR4 listing. Their EPA values come from 84.64 Table 1, and EPA’s program pages sometimes print different figures (for example 4 for R-1234yf on the MVAC page, 3 for propane on SNAP pages).
• Safety class matters as much as GWP. The R-410A replacements in new residential and light commercial AC, R-32 and R-454B, are both A2L. See A2L refrigerants for what changes in handling.
• GWP is not a retrofit guide. A lower-GWP refrigerant still has to suit the equipment, oil and safety listing. See the R-410A replacement and R-22 replacement pages, and refrigerant oil types for lubricant changes.