Refrigerant PT Chart
A refrigerant PT chart gives the pressure at which a refrigerant boils or condenses at each temperature. Read the gauge, find that pressure for your refrigerant, and the chart gives the saturation temperature to compare with the line temperature.
Pressure-temperature charts for eight refrigerants, from R-22 in older systems to R-32 and R-454B in new ones. Every value is computed from the reference data for each refrigerant and checked against NIST and manufacturer tables before it is published.
Pressures compared
Gauge pressure at sea level every 20 °F. Each refrigerant’s own chart has every degree, a lookup, °C, kPa and bar.
| °F | R-22 | R-410A | R-134a | R-404A | R-454B | R-32 | R-290 | R-1234yf |
|---|---|---|---|---|---|---|---|---|
| -20 | 10.2 | 26.3 / 26.2 | 3.7 inHg vac | 16.8 / 16.0 | 24.3 / 22.6 | 26.8 | 10.7 | 0.4 |
| 0 | 24.0 | 48.4 / 48.2 | 6.5 | 33.7 / 32.6 | 45.3 / 42.7 | 49.3 | 23.7 | 9.2 |
| 20 | 43.1 | 78.7 / 78.4 | 18.4 | 56.6 / 55.3 | 73.9 / 70.3 | 80.0 | 41.1 | 21.6 |
| 40 | 68.6 | 118.8 / 118.4 | 35.0 | 86.9 / 85.4 | 112.0 / 107.0 | 121.0 | 63.9 | 38.4 |
| 60 | 101.6 | 170.7 / 170.1 | 57.4 | 126.0 / 124.2 | 161.1 / 154.6 | 174.0 | 93.0 | 60.6 |
| 80 | 143.6 | 236.5 / 235.7 | 86.7 | 175.4 / 173.4 | 223.4 / 215.2 | 241.5 | 129.3 | 89.0 |
| 100 | 195.9 | 318.5 / 317.6 | 124.2 | 236.8 / 234.7 | 300.8 / 290.9 | 325.7 | 173.9 | 124.9 |
| 120 | 260.0 | 419.5 / 418.3 | 171.2 | 312.1 / 309.9 | 395.7 / 384.3 | 429.3 | 227.8 | 169.2 |
Gauge pressure (psig) at sea level; for blends, liquid (bubble) / vapor (dew). Vacuum in inches of mercury.
Which refrigerant is in this unit?
When a system has been off long enough for the refrigerant to reach the air temperature, and there is still liquid in it, its pressure is the saturation pressure at that temperature. Enter the two readings and the tool lists which of the eight refrigerants fit, and how far off the others are.
Which refrigerant matches this reading?
Enter the air temperature and the gauge pressure of a unit that has been off long enough to reach that temperature.
When there is no match, or the match looks wrong:
- The unit has not settled. A system that ran recently is not yet at air temperature. Wait and read again.
- No liquid is left. With vapor only, the pressure is below the chart value, so the reading is low.
- Air or another gas is in the system. A gas that does not condense adds its own pressure, so the reading is high.
- Refrigerants have been mixed. A mix usually matches neither chart.
- Two refrigerants are close. Some sit within a few degrees of each other at some temperatures. The tool lists every match; the nameplate settles it.
Choose a refrigerant
| Refrigerant | Type | Safety class | GWP-100 (AR6) |
|---|---|---|---|
| R-22 PT chart | HCFC, single compound | A1 | 1960 |
| R-410A PT chart | HFC blend | A1 | 2256 |
| R-134a PT chart | HFC, single compound | A1 | 1530 |
| R-404A PT chart | HFC blend | A1 | 4728 |
| R-454B PT chart | HFC/HFO blend | A2L | 531 |
| R-32 PT chart | HFC, single compound | A2L | 771 |
| R-290 PT chart | Hydrocarbon (propane) | A3 | 0.02 |
| R-1234yf PT chart | HFO, single compound | A2L | 0.501 |
Safety classes are ASHRAE 34 designations: A = lower toxicity; 1 = no flame propagation, 2L = lower flammability, 3 = higher flammability. GWP from our refrigerant GWP dataset.
Since 1 January 2025, new US residential and light-commercial air-conditioners and heat pumps must use a refrigerant with a global warming potential below 700. R-410A is above it, and the main replacements are R-32 and R-454B; existing R-410A systems can still be serviced. The R-410A, R-32 and R-454B section of our GWP dataset gives the dates and rules.
How to read a PT chart
Where liquid and vapor are both present, as in an evaporator, a condenser or a cylinder, a refrigerant’s pressure and temperature are tied together. The chart lists that saturation pressure for each temperature, so a gauge reading tells you the temperature the refrigerant is boiling or condensing at.
Superheat is the suction line temperature minus the saturation temperature at the suction pressure. Subcooling is the saturation temperature at the liquid line pressure minus the liquid line temperature. Each refrigerant’s page works both out for you and has a worked example. Whether a figure is right for a system depends on that system: compare with the manufacturer’s charging instructions.
Blends: liquid and vapor
R-410A, R-404A and R-454B are blends, and a blend boils over a range of temperatures. Their charts have two columns: the liquid (bubble point) pressure, where the first bubble forms, and the vapor (dew point) pressure, where the last drop boils. Use the vapor value for superheat and the liquid value for subcooling. The gap, or glide, is small for R-410A (0.2 °F at 40 °F), larger for R-404A (0.9 °F) and R-454B (2.3 °F).
Elevation
A gauge reads the refrigerant’s pressure minus the air pressure around it, and air pressure falls with height. At 5,000 ft the standard atmosphere is 12.23 psia instead of 14.70, so a gauge reads about 2.5 psi higher for the same refrigerant temperature. Set your elevation in the lookup above, or on any refrigerant’s page, and the values switch to it.
Questions about refrigerant PT charts
A pressure-temperature chart lists the pressure at which a refrigerant boils or condenses at each temperature, its saturation pressure. Technicians use it to turn a gauge reading into a saturation temperature for superheat and subcooling.
At 40 °F and sea level, R-32 is highest of the eight on this page, at 121.0 psig, against 118.8 psig for R-410A (liquid). R-134a and R-1234yf are lowest, at 35.0 and 38.4 psig.
A blend boils over a range of temperatures. The liquid (bubble point) pressure is where the first bubble forms; the vapor (dew point) pressure is where the last drop boils. Use the vapor value for superheat and the liquid value for subcooling.
No. Each refrigerant has its own pressure at a given temperature, and a system is designed for one refrigerant. Use the chart for the refrigerant on the nameplate.
Seven of the eight are computed with CoolProp 8.0.0 from each refrigerant’s reference equation of state. R-454B is Chemours’ published table. Every gas was compared with independent tables from NIST, Arkema, Chemours or Daikin before publishing; each page shows the comparison.
Version history
- 1.1.1 (29 October 2026): sources moved into a compact card at the end of the page, so they no longer break up the reading.
- 1.1 (28 October 2026): tool to match a standing pressure to a refrigerant.
- 1.0 (28 October 2026): first published.