The heating, ventilation and cooling (HVAC) industry uses some rather confusing terms, one of which is superheat. It’s used in conjunction with air conditioning systems and heat pumps.

Air conditioning systems and heat pumps both leverage refrigerant to cool the homes in which they are installed. They absorb heat from inside the homes, and refrigerant will carry this heat to the outdoors where it’s released at the condenser unit. Superheat, however, will affect the refrigerant’s ability to absorb and transfer heat.

What Is Superheat?

Superheat is the difference between the actual temperature of a gas substance and the saturation temperature of that same substance.

Liquids will turn to gas when heated to a high enough temperature. Water, for instance, turns to steam at 212 degrees Fahrenheit. This same principle applies to refrigerant in air conditioning systems and heat pumps. If it gets hot enough, refrigerant will turn from a liquid state to a gas state. Air conditioning systems are actually designed to use refrigerant in both a liquid and gas state. As refrigerant travels through the coils, it will transition between these two states.

When used in the context of HVAC systems, superheat is the difference between the temperature of refrigerant in a gas state and the refrigerant’s saturation temperature. Generally speaking, it offers insight into heat absorption. Superheat reveals how much heat the refrigerant has absorbed.

How Superheat Affects Your AC System

Refrigerant needs to boil off after leaving the evaporator coil. This will allow the condenser coil to release more heat while simultaneously protecting the compressor from damage. If liquid refrigerant enters the compressor, it may cause damage that’s difficult and expensive to fix. Therefore, air conditioning systems and heat pumps are designed to boil off refrigerant as it leaves the evaporator coil and heads to the condenser coil.

If the superheat is too high, it means there’s more liquid refrigerant in your air conditioning system. If this liquid refrigerant makes its way to the compressor, it may cause damage. If the superheat is too low, conversely, it means there’s more gas refrigerant in your air conditioning system.

HVAC technicians can use superheat to determine the temperature at which refrigerant will boil off and, thus, turn to steam. As a homeowner, you don’t need to worry about your air conditioning system’s superheat. Superheat is an HVAC industry term that’s typically used for troubleshooting cooling problems.