Global warming potential
GWP
Global warming potential (GWP) compares how much heat a gas traps in the atmosphere with the same mass of carbon dioxide; U.S. rules limit new home air conditioners and heat pumps to refrigerants with a GWP of 700 or less.
Carbon dioxide has a GWP of 1 by definition. A refrigerant with a GWP of 2,090 traps that many times more heat than the same mass of CO₂ over the reference period, which is why leaks of refrigerant matter even though the quantities are small.
EPA’s rules under the AIM Act set GWP limits by use. For new residential and light commercial air conditioning and heat pump systems made or imported from January 1, 2025, the limit is 700.
| Refrigerant | GWP listed by EPA SNAP |
|---|---|
| R-410A | 2,090 |
| R-452B | 700 |
| R-32 | 675 |
| R-454B | 470 |
Values in different documents can differ slightly depending on which scientific assessment they use, so a figure is best quoted with its source.
Sources
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