10 refrigerants · cited to the annexes
Refrigerant GWP table
Global warming potential for the refrigerants found in UK commercial buildings, taken from the F-Gas annexes rather than from commentary — with the Great Britain and Northern Ireland figures side by side, because for 4 of them they are not the same.
| Refrigerant | Composition | GWP (Great Britain) | GWP (EU / Northern Ireland) | Safety |
|---|---|---|---|---|
| R-32 | Difluoromethane | 675 | 675 | A2L |
| R-410A | R-32/125 (50/50) | 2,088 | 2,088 | A1 |
| R-407C | R-32/125/134a (23/25/52) | 1,774 | 1,774 | A1 |
| R-134a | 1,1,1,2-tetrafluoroethane | 1,430 | 1,430 | A1 |
| R-404A | R-125/143a/134a (44/52/4) | 3,922 | 3,922 | A1 |
| R-454B | R-32/1234yf (68.9/31.1) | 466.3 | 465.2 | A2L |
| R-513A | R-1234yf/134a (56.0/44.0) | 631.4 | 629.5 | A1 |
| R-1234yf | 2,3,3,3-tetrafluoropropene | 4 | 0.501 | A2L |
| R-290 | Propane | 3 | 0.02 | A3 |
| R-744 | Carbon dioxide | 1 | 1 | A1 |
Highlighted values differ between the regimes. Blend GWPs are computed by the mass-weighted method both regulations set out, from the component values in their own annexes; each refrigerant's page shows the arithmetic. Compositions from ASHRAE Standard 34.
Frequently asked questions
Which IPCC assessment report do these values use?
The Fourth (AR4), for the saturated HFCs, in both regimes. Annex I of Regulation (EU) 2024/573 carries the footnote "Based on the Fourth Assessment Report adopted by the Intergovernmental Panel on Climate Change", and the retained Great Britain Annex I is identical. Claims that the EU moved to AR5 on 1 January 2025 — putting R-410A at 1924 rather than 2088 — do not describe the basis the regulation applies. Where a substance's value does come from a later report, the annex says so, and the table above shows the difference.
Why do some refrigerants have two different GWPs here?
Because Great Britain and Northern Ireland are under different F-Gas regimes after the Windsor Framework, and the two instruments value the unsaturated compounds differently. R-1234yf is 4 in the retained GB annex and 0.501 in the EU one; propane is 3 against 0.02. That moves any blend containing them, which is why R-454B and R-513A differ by about a point between regimes. The saturated HFCs — R-32, R-125, R-134a, R-143a — are identical in both.
How do I turn a GWP into a leak-check frequency?
Multiply the charge in kilograms by the GWP and divide by 1,000 to get tonnes CO₂e. From 5 tonnes the equipment must be checked at least every 12 months, from 50 tonnes every 6 months, and from 500 tonnes every 3 months — where an automatic leak detection system also becomes mandatory. Fitting leak detection doubles the interval at every band. Each refrigerant's page converts those bands back into a charge in kilograms.
Are R-290 and R-744 covered by F-Gas?
No. Propane and carbon dioxide are not fluorinated greenhouse gases, so the F-Gas leak-check thresholds do not apply to them in either regime — there is no charge at which a statutory F-Gas leak check is triggered. They appear in the annexes only so that the GWP of a mixture containing them can be calculated. What governs those systems is flammability for propane and pressure and asphyxiation risk for CO₂, from the relevant safety standard and the site risk assessment.