| R134a | R1234yf | R1234yf + CF3I | R744 | |
| Chemical formula | CF3-CFH2 | CF3CF=CH3 | CF3CF=CH3/CF3I | CO2 |
| Toxicity | no | no | yes | no |
| Flammability | no | yes | no | no |
| GWP | 1300 | 3 - 4 | 3 - 4 | 1 |
| Reactivity with Lithium | yes | yes | yes | no |
| Usable in current MAC systems | Currently standard | yes | yes | No; re-design necessary |