What does high superheat and low subcooling in an air conditioning system typically indicate?

High superheat combined with low subcooling in an air conditioning system generally indicates that the system is starved for refrigerant, which is often associated with a need for additional refrigerant (Freon) to be added. Superheat measures the degree to which the refrigerant vapor has been heated beyond its boiling point in the evaporator; high superheat suggests that there is not enough refrigerant in the evaporator to absorb the heat from the indoor air properly. On the other hand, low subcooling indicates that there isn't enough refrigerant in the condenser to adequately remove heat and ensure proper pressure levels in the system.

Therefore, the combination of these two factors typically points to insufficient refrigerant levels. This situation can lead to inefficient system operation, reduced cooling performance, and potentially damage to the compressor if not addressed. Refilling the system with refrigerant is a common corrective action in this scenario.