The disclosed technology includes devices and systems for an air conditioning unit having a subcooling line. The disclosed technology can include a heat exchanger coil, a bypass line, and a subcooling line. A first valve can be in fluid communication with the subcooling line and a second valve can be in fluid communication with the bypass line. When the air conditioning unit is operating in a cooling mode, the first valve can be configured to permit refrigerant to flow through the subcooling line and the second valve can be configured to prevent refrigerant from flowing through the bypass line. When the air conditioning unit is operating in a heating mode, the first valve can be configured to prevent refrigerant from flowing through the subcooling line and the second valve can be configured to permit refrigerant to flow through the bypass line.