What is Sub-cooling and Super-heating ?

subcooling and super heat chart miami

Sub-cooling and Super-heating this is the best way to diagnose your unit and is a crucial factor in getting the right diagnoses. Freon transitions from a liquid state to gas form as it passes through the system.  In between liquid and gas there is a saturation level which usually takes place in both coils where either the heat is extracted or the heat is absorbed

What is Sub-Cooling? Sub Cooling is the state of the Freon once it I has been brought to below the boiling point and in a sub cooling state the Freon is full liquid. Sub cooling is checked by the degrees below saturation

What is Super –heated? Super-heated is when the Freon passes the boiling point and has converted completely to gas form, superheating degrees is checked by the temp above full saturation.


Many times by checking your super-heating and sub-cooling you can properly diagnose a unit they are the best indicators to see if your unit is running correctly. Many technicians today do not always check but if you want to get the most information about your unit and how it’s working always checks those levels.

As a homeowner you can always check you super heating levels to possibly self-diagnose the unit yourself.  Here is a link for a gauge to properly check you sub cooling and superheated levels.