Subcooling is the difference between the measured temperature of a refrigerant and the temperature at which it would boil at a given pressure, as determined by referencing the refrigerant's pressure-temperature chart. For example, if the measured temperature of R-22 refrigerant is 110°F at 260 pounds per square inch gauge (PSIG) pressure, the chart shows the boiling point is 120°F at that pressure, so the subcooling is 10°F (computed as 120°F - 110°F = 10°F).