Work out superheat and subcooling instantly with clear inputs, formula shown and shareable results.
Superheat is how far the suction vapour has been heated above its saturation temperature, and subcooling is how far the liquid has been cooled below it. Together they show whether the charge and metering device are matching the evaporator load: superheat reads the evaporator side, subcooling reads the condenser side.
Superheat
Superheat = suction line temp - evaporator saturation temp
Subcooling
Subcooling = condenser saturation temp - liquid line temp
Superheat = suction line temp - evaporator saturation temp. Superheat is how far the suction vapour has been heated above its saturation temperature, and subcooling is how far the liquid has been cooled below it.
On a TXV or EEV system charge by subcooling, because the valve holds superheat constant. On a fixed orifice system charge by superheat using the manufacturer's target chart.
This calculator takes 4 inputs: Suction line temperature, Evaporator saturation temperature, Liquid line temperature, Condenser saturation temperature. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.