The air conditioning system with solar-powered subcooling system includes a main cooling system having an evaporator, a compressor, a condenser, and an expansion valve configured to operate in a conventional vapor compression refrigerant cycle. The subcooling system includes a compressor, a condenser, and an expansion valve, the compressor being powered by at least one rechargeable battery connected to a photovoltaic solar panel. The main system and the subcooling system are linked by a heat exchanger having a primary coil in the main system between the condenser and the expansion valve and a secondary coil in the subcooling system disposed between the expansion valve and the compressor. The main system and the subcooling system may use the same type of refrigerant, or different refrigerant types. The additional cooling provided to the refrigerant in the main system by subcooling increases the efficiency of the air conditioning system.