What are GWP and ODP? And why do the numbers differ between documents?
The two key figures for a refrigerant's environmental impact, and why GWP values from IPCC AR4 and AR5 are not the same.
ODP — Ozone Depletion Potential
How much a substance damages the ozone layer, relative to R-11 (ODP = 1).
- HCFCs such as R-22 (ODP 0.055) and R-141b (ODP 0.11) still deplete ozone, so they are being phased out under the Montreal Protocol.
- HFCs, HFOs and HCs have zero or near-zero ODP.
GWP — Global Warming Potential
How much heat 1 kg of a gas traps in the atmosphere compared with 1 kg of CO₂, over 100 years.
- R-404A has a GWP of about 3,922 — a 1 kg leak has roughly the climate impact of 3.9 tonnes of CO₂.
- HFOs such as R-1234yf have ultra-low GWP (below 1 to 4).
- Phasing down high-GWP HFCs is the goal of the Kigali Amendment to the Montreal Protocol.
Why does one refrigerant have several GWP values?
GWP values come from IPCC assessment reports, which are updated over time. The most commonly used are AR4 (2007) and AR5 (2013), for example:
| Refrigerant | GWP (AR4) | GWP (AR5) |
|---|---|---|
| R-404A | 3,922 | 3,943 |
| R-410A | 2,088 | 1,924 |
| R-448A | 1,387 | 1,273 |
| R-32 | 675 | 677 |
So a "% lower GWP" figure can differ slightly between documents depending on the basis — R-448A versus R-404A is about 65% lower on AR4 or 68% on AR5. This website shows AR4 values by default and lists AR5 in each product's specification table.
Browse low-GWP products in all products.