R22 vs R290 Refrigerant Comparison — Pressure, GWP, Safety
| Spec | R22 | R290 |
|---|---|---|
| Type | HCFC | HC (Propane) |
| GWP | 1,810 | 3 |
| Ozone Depletion | 0.055 | 0 |
| Safety Class | A1 | A3 |
| Boiling Point | -41.4°F | -43.7°F |
| Critical Temp | 204.8°F | 206.1°F |
| Status | Phased out | Growing adoption |
Key Differences
R22 GWP 1,810 vs R290 GWP 3
Advantage: R290
R22 operates at standard pressures; R290 at standard pressures
R22: ASHRAE A1 (non-flammable); R290: ASHRAE A3
Advantage: R22
Recommendation
R290 has a lower GWP (3) compared to R22 (1,810). For new equipment purchases, R290 is the more future-proof choice given AIM Act HFC phase-down requirements. For retrofit/drop-in replacement in existing systems, consult the manufacturer's approved refrigerant list before switching.
Never mix refrigerants in a system. Mixing causes unpredictable pressure-temperature behavior, oil contamination, and potential acid formation. Always recover all refrigerant before switching types. Systems designed for R-22 typically require oil changes and component verification before accepting HFC alternatives.
Purchase and handling of refrigerants in containers larger than 2 lbs requires EPA Section 608 certification (Type I, II, or Universal depending on equipment type). Intentional venting of any refrigerant to atmosphere is illegal under the Clean Air Act.
Before substituting one refrigerant for another, verify: (1) compressor oil compatibility — POE oil required for most HFCs; (2) metering device adjustment — TXVs may need rerating; (3) system pressure ratings — some alternatives operate at higher pressures; (4) material compatibility — elastomers, gaskets, and seals must be rated for the new refrigerant.