What the result means
Superheat is the difference between the measured suction-line temperature and the refrigerant’s saturated vapor (dew) temperature at the measured suction pressure.
This calculator supplies the arithmetic and pressure lookup only. It does not select a target or replace manufacturer charging instructions or operating-condition checks.
How it's calculated
- Saturation temperature = dew-point temperature at suction pressure
- Superheat = suction-line temperature − saturation temperature
Pressure-to-temperature lookup uses the committed refrigerant data and linear interpolation between 1°F rows.
For R-454B, the committed saturation data comes from the Chemours Opteon XL41 table; other chart fluids use the listed CoolProp-generated values.
Worked example
R-410A at 118 psig with a measured suction-line temperature of 50°F.
- The dew saturation temperature at 118 psig is about 39.8°F.
- Superheat = 50.0°F − 39.8°F = 10.2°F.
Calculated superheat = 10.2°F. Compare it with the equipment-specific target from the manufacturer.
Reference table
The values below are computed from the same calculator functions used above. They let you compare common sizes and operating points without replacing the interactive calculation or its assumptions.
| Refrigerant | Suction pressure | Line temperature | Dew saturation temperature | Superheat |
|---|---|---|---|---|
| R-410A | 118 psig | 50°F | 39.8°F | 10.2°F |
| R-454B | 106.98 psig | 52°F | 40.0°F | 12.0°F |
Examples verify the dew-temperature lookup and subtraction only. Follow the equipment manufacturer's charging procedure for the target.
Sources and assumptions
Pressure-to-temperature lookup uses the committed refrigerant data and linear interpolation between 1°F rows. For R-454B, the committed saturation data comes from the Chemours Opteon XL41 table; other chart fluids use the listed CoolProp-generated values. Calculator formulas are published with their units so a technician can check a result instead of treating it as a black box. Where a code table, manufacturer specification or field measurement is required, use the applicable local source.
Last reviewed . Spot an error? Email support@tiermenu.com.
FAQ
Which saturation column does superheat use?
The dew column, corresponding to saturated vapor temperature, is used for suction-pressure superheat calculations.
Does this calculator provide a target superheat?
No. Use the manufacturer’s charging chart for a fixed-orifice system or the TXV setting, together with the required operating conditions.
What if pressure is outside the supplied chart?
No saturation temperature or superheat is returned outside the committed −40°F to 150°F data range. Negative gauge pressure is shown as vacuum in inches of mercury.
Which refrigerants are included?
The supplied tables cover R-410A, R-454B, R-32 and R-22 from −40°F through 150°F.
What service precautions apply?
R-454B and R-32 are A2L refrigerants. Follow required A2L service procedures and the equipment manufacturer’s instructions.
Using a reference result in the field
A calculator is most useful when the inputs match the job being checked. Confirm the refrigerant, where each pressure and temperature reading was taken, and that the system is at the operating conditions the manufacturer specifies. The unit label beside the result is part of the result; do not carry a number into another calculation without checking its units.
Reference rows are provided for comparison, not as universal design limits. They use the values and conditions stated with each table. Gauge accuracy, probe placement and operating conditions can change a field result. Where the page calls out a code check, equipment rating or manufacturer table, that check remains part of the job.
Use the interactive inputs for the exact conditions at hand, then review the displayed formula and assumptions. If a value looks unexpected, change one input at a time and compare it with a known point in the reference table. Keep the measured readings and job-specific notes with the work record so another technician can understand how the result was obtained.
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