Calculator
Select the refrigerant, then enter the suction side and liquid side readings so the calculator can compare line temperature with saturation temperature from pressure. It is a quick way to check superheat and subcooling together while you follow the equipment target.
- Select refrigerant
- Suction side
- Liquid side
For a step-by-step walkthrough, see how to calculate superheat and subcooling, or review the refrigerant PT chart and refrigerant log.
Formulas
Superheat uses the suction line temperature and the saturation temperature tied to suction pressure. Subcooling uses the saturation temperature tied to liquid pressure and the liquid line temperature. The calculator applies those comparisons after you enter the readings.
- Superheat
- Subcooling
If you want the plain-language version, the glossary explains the terms used on the page.
Where to measure
Measure superheat on the suction line near the evaporator outlet or compressor, and measure subcooling on the liquid line near the condenser outlet. Good contact with the pipe and a stable reading make the result easier to trust.
Reading the result
What counts as a good superheat or subcooling depends on the equipment and the target you are following. Use the calculator as a guide, then compare the result with the system instructions rather than a single universal number.
Blends and glide
For blended refrigerants, use the temperature type that matches the side you are checking. In general, that means dew side for suction and bubble side for liquid, then follow the equipment target and the reference you trust.
Want more reminders and record keeping in one place? See get the app and the home page.
Reference only. Verify with manufacturer data and gauges. Follow the manufacturer chart and EPA rules. This site is not an approval from EPA.