Subcooling is a technical measurement used by HVAC professionals to determine if a system has the correct refrigerant charge. It represents the difference between the temperature of the liquid refrigerant and its saturation temperature. Proper subcooling ensures that only liquid refrigerant reaches the expansion valve, which is necessary for the evaporator coils to function at peak efficiency. This measurement is especially important for our central condensers air conditioner condenser units where line set lengths can vary significantly. If the subcooling is off, your system may struggle to cool during a heatwave. We provide detailed technical charts for our heat pump condensers to help techs dial in the perfect charge.