R1234yf vs R134a pressure temperature chart (PT)
This page compares the saturation pressure vs temperature relationship for R1234yf and R134a. Both appear in automotive A/C discussions. The table below is a property reference only — it is not a “normal operating pressure” diagnostic chart.
Pressure basis: absolute vs gauge
Values are absolute pressure (kPa(a), bar(a), psi(a)). Many field gauges display gauge pressure (relative to ambient). Converting requires local atmospheric pressure:
Learn more: Gauge vs absolute pressure (psig vs psia).
R1234yf vs R134a saturation PT (comparison table)
Generated using CoolProp (the same property engine used by FluidTool) at Q=0 saturation. Values are rounded for readability.
| T (°C) | T (°F) | R1234yf Psat (kPa(a)) | R134a Psat (kPa(a)) | ΔPsat (kPa(a)) | R1234yf (bar(a)) | R134a (bar(a)) | R1234yf (psi(a)) | R134a (psi(a)) |
|---|---|---|---|---|---|---|---|---|
| -20 | -4 | 150.9 | 132.7 | +18.2 | 1.509 | 1.327 | 21.9 | 19.3 |
| -10 | 14 | 221.8 | 200.6 | +21.2 | 2.218 | 2.006 | 32.2 | 29.1 |
| 0 | 32 | 315.8 | 292.8 | +23.0 | 3.158 | 2.928 | 45.8 | 42.5 |
| 10 | 50 | 437.5 | 414.6 | +22.9 | 4.375 | 4.146 | 63.5 | 60.1 |
| 20 | 68 | 591.7 | 571.7 | +20.0 | 5.917 | 5.717 | 85.8 | 82.9 |
| 30 | 86 | 783.5 | 770.2 | +13.3 | 7.835 | 7.702 | 113.6 | 111.7 |
| 40 | 104 | 1018.4 | 1016.6 | +1.8 | 10.184 | 10.166 | 147.7 | 147.4 |
| 50 | 122 | 1302.3 | 1317.9 | -15.6 | 13.023 | 13.179 | 188.9 | 191.1 |
| 60 | 140 | 1641.9 | 1681.8 | -39.9 | 16.419 | 16.818 | 238.1 | 243.9 |
| 70 | 158 | 2044.5 | 2116.8 | -72.3 | 20.445 | 21.168 | 296.5 | 307.0 |
Safety note (automotive context)
Refrigerant choice and service procedures depend on system design, regulations, and safety requirements. This page provides thermodynamic property reference data only and does not recommend retrofits, targets, or operating pressures.
How to verify any row in FluidTool
- Open FluidTool with R1234yf selected: /?fluid=R1234YF
- Choose a Two-phase input pair (Temperature & Quality / T + Q) and set Q=0.
- Enter the temperature from the table to read Psat. Repeat for /?fluid=R134A.
Related
- R1234yf PT chart: the single-fluid saturation table for R1234yf.
- R134a PT chart: the single-fluid saturation table for R134a.
- Car A/C pressure chart: how PT data is used (and commonly misused) in automotive A/C discussions.
- Refrigerant PT chart: the core interpretation principles and pitfalls (gauge vs absolute, blends, non-saturation).
- R1234yf data sheet, R134a data sheet: identifiers and context.