Verified HVAC/R Thermodynamic Reference

Refrigerant Pressure-Temperature Chart

Look up refrigerant saturation pressure from temperature, or saturation temperature from pressure, with bubble and dew point data for refrigerant blends.

Thermodynamic reference only. This P-T chart is not a refrigerant charging target, equipment operating-pressure specification, diagnosis procedure or equipment approval.
Verified Launch Dataset

16 refrigerants with source-controlled curves

This first version intentionally supports fewer refrigerants than the other site calculators. P-T data is included only where the source curve can be normalized and checked reliably.

T → PTemperature to saturation pressure
P → TPressure to saturation temperature
Bubble / DewSeparate blend reference curves
6 pressure unitsGauge and absolute clearly separated
Interactive P-T Lookup

Pressure and temperature in either direction

Select a refrigerant, choose the lookup direction and units, then calculate within the verified embedded range. The tool interpolates only between source points and does not extrapolate beyond them.

Lookup Direction
Lookup Result

R410A at 25°C

Source-controlled embedded curve
Bubble Pressure Saturated liquid reference
Dew Pressure Saturated vapor reference
Refrigerant / Safety
Verified Range No extrapolation outside this range
Bubble and dew point: Bubble is the saturated-liquid reference; dew is the saturated-vapor reference. For pure refrigerants the values coincide.
R410A P-T Curve Pressure vs Temperature
Reference Context

Open Technical Source →
Nearby P-T Reference Points
How to Read the Data

Four concepts behind a refrigerant P-T chart

A P-T chart links saturation pressure and saturation temperature. For blends, the liquid and vapor saturation boundaries can differ.

What is a refrigerant P-T chart?

A pressure-temperature chart shows the saturation relationship between refrigerant pressure and temperature. At saturation, liquid and vapor phase conditions are connected by the refrigerant's thermodynamic properties.

Temperature → Saturation Pressure   |   Pressure → Saturation Temperature

Bubble point vs dew point

Bubble point is the saturated-liquid reference. Dew point is the saturated-vapor reference. Zeotropic blends such as R407C, R448A and R449A can have meaningfully different bubble and dew curves.

Bubble = saturated liquid   |   Dew = saturated vapor

Gauge vs absolute pressure

Gauge pressure is referenced to local atmospheric pressure; absolute pressure is referenced to vacuum. This tool uses 101.325 kPa as standard atmosphere for conversions.

psig = psia − 14.6959488   |   bar(g) = bar(a) − 1.01325

How should the tool be used?

Choose the exact refrigerant, select a known temperature or pressure, and read the corresponding saturation reference. For blends, keep bubble and dew values distinct.

P-T reference ≠ charging specification ≠ normal operating pressure
Review Refrigerant Safety →
Verified Coverage

Refrigerants included in this launch version

P-T curves are included only when an official manufacturer or NIST source can be normalized into a consistent absolute-kPa dataset.

R410ANear-azeotropic · A1
R32Pure HFC · A2L
R134aPure HFC · A1
R22Pure HCFC · A1
R404ANear-azeotropic blend · A1
R407CZeotropic blend · A1
R448AZeotropic HFO/HFC blend · A1
R449AZeotropic HFO/HFC blend · A1
R452AZeotropic HFO/HFC blend · A1
R454BZeotropic HFO/HFC blend · A2L
R513AAzeotropic blend · A1
R507AAzeotropic blend · A1
R290Pure hydrocarbon · A3
R600aPure hydrocarbon · A3
R717Pure ammonia · B2L
R1233zd(E)Pure HCFO · A1
Why is R744 not shown yet? CO₂/R744 requires careful treatment of the subcritical saturation region and its critical point. This first version does not synthesize an R744 curve merely to increase the refrigerant count. A verified subcritical dataset should be added before R744 is exposed in this tool.
Technical Sources

Where the embedded P-T curves come from

Source tables are normalized to absolute kPa before they are embedded. Browser-side interpolation occurs only between those stored points.

Manufacturer / REFPROP Arkema 2025 Forane Technical Digest

P-T tables for R22, R32, R134a, R407C, R410A, R448A, R449A, R452A, R454B, R513A and R1233zd. Arkema states the chart data was generated using NIST REFPROP 10.0.

Open Arkema source →
Manufacturer Honeywell Pressure-Based P-T Charts

Pressure-based bubble/dew data used for R404A and saturation data for R507A, normalized from psig/°F to absolute kPa/°C.

Open Honeywell source →
NIST NIST Chemistry WebBook

NIST-published Antoine correlations are sampled within their documented coefficient ranges for R290, R600a and R717.

Open NIST Chemistry WebBook →
FAQ

Pressure-temperature chart questions

Concise answers for saturation pressure, bubble/dew values and P-T units.

What is a refrigerant P-T chart?

A refrigerant P-T chart relates saturation pressure to saturation temperature. It is a thermodynamic reference, not an equipment operating-pressure specification.

How do I find refrigerant pressure from temperature?

Select Temperature → Pressure, choose the refrigerant and enter temperature. The tool interpolates only within the verified embedded curve.

How do I find saturation temperature from pressure?

Select Pressure → Temperature and enter the pressure with the correct gauge or absolute unit. Blends return bubble and dew temperatures separately.

What is the difference between psig and psia?

psig is gauge pressure; psia is absolute pressure. This tool uses 14.6959488 psi as standard atmospheric pressure for conversion.

What is bubble point?

Bubble point is the saturated-liquid reference condition. For zeotropic blends it can differ noticeably from the dew point.

What is dew point?

Dew point is the saturated-vapor reference condition. It should not be silently substituted with bubble point for a meaningful-glide blend.

Why does R407C have bubble and dew values?

R407C is a zeotropic blend with temperature glide. Its saturated-liquid and saturated-vapor boundaries therefore differ at a given pressure.

Does R410A have temperature glide?

R410A is near-azeotropic and has very small glide. The Arkema source used here publishes one R410A saturation-pressure curve, represented as aligned bubble/dew values in this tool.

What pressure is R410A at 25°C?

Approximately 15.57 bar(g) on this embedded Arkema/REFPROP-derived curve, obtained by interpolation between the surrounding source points.

What pressure is R32 at 25°C?

Approximately 15.89 bar(g) on this embedded Arkema/REFPROP-derived curve, obtained by interpolation between the surrounding source points.

Why is R744 not in this first version?

R744 needs careful subcritical and critical-region handling. The site will add it when a suitable verified embedded saturation dataset is prepared rather than generating an unsupported curve.

Can a P-T chart tell me the correct refrigerant charge?

No. A P-T chart is a thermodynamic saturation reference, not a refrigerant charging specification. Use OEM equipment and service documentation for real-system decisions.

This P-T chart is a thermodynamic reference tool. It is not a refrigerant charging target, equipment operating-pressure specification, diagnosis procedure or equipment approval. Verify the exact refrigerant identity, current OEM documentation, technical data, applicable safety standards and equipment service documentation before making real-system decisions.
Refrigerant Research Support

Need help comparing refrigerant properties or selecting a lower-GWP route?

Use the Refrigerant Comparison Tool for broader technical differences, the Finder for application screening, or discuss refrigerant selection and project requirements.