Will AC stop working if refrigerant is low?

Yes, an air conditioning system or heat pump will eventually stop working or fail to cool effectively if its refrigerant charge becomes severely depleted. While a system with slightly low refrigerant may continue running for a while, it will struggle to absorb heat from your home, resulting in long, continuous runtimes and poor cooling performance. As the refrigerant level drops further, the pressure inside the evaporator coil decreases significantly, causing the temperature of the coil to fall below freezing. This low temperature freezes any moisture condensing on the coil, turning the indoor evaporator into a solid block of ice, which completely blocks airflow and forces safety controls to shut the system down. Additionally, running a compressor with low refrigerant starves it of the cooling and lubrication provided by the gas, risking catastrophic compressor burnout. You can verify this by checking for iced coils.