What are the GWP values of R-22, R-32, R-410A, R-134a and R-404A?
What GWP measures
Global Warming Potential compares one kilogram of a gas against one kilogram of CO₂ over a chosen horizon — conventionally 100 years. GWP 1,810 means a kilogram of R-22 traps as much heat over a century as 1.81 tonnes of CO₂. The metric drives modern refrigerant policy: Kigali quotas, EU F-Gas rules and corporate Scope-1 accounting all run on GWP-weighted tonnage.
The reference table
| Refrigerant | Composition | GWP (AR4) | GWP (AR5) | Notes |
|---|---|---|---|---|
| R-22 | HCFC-22 | 1,810 | 1,760 | Also ODP 0.055 — the only ozone-depleter here |
| R-32 | HFC-32 | 675 | 677 | Kigali Annex F lists 675 |
| R-410A | 50% R-32 / 50% R-125 | 2,088 | — | Mass-weighted blend value |
| R-134a | HFC-134a | 1,430 | 1,300 | Annex F lists 1,430 |
| R-404A | 44% R-125 / 52% R-143a / 4% R-134a | 3,922 | — | Highest-GWP mainstream refrigerant |
Key component values behind the blends (AR4): R-125 = 3,500; R-143a = 4,470. A blend's GWP is simply the mass-weighted sum of its components — e.g. R-410A: 0.5×675 + 0.5×3,500 = 2,088.
AR4 vs AR5 — and why both numbers circulate
The IPCC re-estimates GWPs each assessment cycle as atmospheric science sharpens; AR4 (2007) and AR5 (2013) therefore differ — R-134a drops from 1,430 to 1,300, R-22 from 1,810 to 1,760. Regulation, however, is frozen to AR4: Kigali's Annex F adopted AR4 values so national quotas would not shift with each report. So a compliance document citing 1,430 for R-134a and a scientific paper citing 1,300 are both right — they are answering different questions. Flag: blend values like 2,088 and 3,922 are calculated sums, not figures listed in Annex F itself, which contains only pure substances.
Using GWP in buying decisions
GWP is now a cost signal, not just an environmental one: Kigali counts CO₂-equivalents, so a kilogram of R-404A draws 5.8× the quota of R-32 — the arithmetic behind the industry's R-32 migration and the pressure on cold-chain operators to consider R-407A/F retrofits (see cold-storage refrigerants). For leak-audit and ESG reporting, multiply kilograms lost by AR4 GWP and you have the CO₂e figure your auditor expects.
Using the numbers: a leak, in CO₂-equivalent terms
Worked example, because the arithmetic is where GWP becomes real. A mid-size cold room loses 10 kg of R-404A over a year through a slow flange leak. CO₂-equivalent: 10 kg × 3,922 = 39.2 tonnes CO₂e — roughly the annual tailpipe output of eight or nine passenger cars, from one unglamorous leak. The same 10 kg lost from an R-32 split-AC estate: 10 × 675 = 6.75 tonnes CO₂e — a factor of 5.8 difference for identical kilograms. This is the calculation behind three things buyers increasingly meet. ESG and Scope-1 reporting: refrigerant losses multiplied by AR4 GWP are a standard emissions line; auditors expect purchase and top-up records to support the figure. Leak economics: as Kigali repricing arrives, the CO₂e-heavy gases carry the steepest per-kg cost growth, so leak-tightness on R-404A plant pays twice — avoided gas cost and avoided reporting burden. Specification drift: corporate buyers now write maximum-GWP clauses into HVAC tenders, which is how GWP moved from an environmental footnote to a line item in commercial negotiations. One caution when using any table, including ours: state the assessment-report basis. 'GWP of R-134a' is ambiguous; 'GWP 1,430 (AR4, Kigali reporting basis)' is auditable — and the difference between the two habits is the difference between a defensible report and a correction letter.
- Kigali Amendment Annex F (official text, AR4 GWP values: HFC-32 = 675, HFC-125 = 3,500, HFC-134a = 1,430) — ozone.unep.org.
- IPCC Fourth Assessment Report (2007) and Fifth Assessment Report (2013), WG1 GWP tables.
- US EPA — GWP reference materials — epa.gov.
This guide is general information compiled from the cited sources — not legal, safety or engineering advice. Read our full disclaimer.
Related: ODP values · Kigali schedule · R-32 supply