Why is my AC line frozen?

Why is my AC line frozen refers to ice buildup on suction line or liquid line or evaporator coil, common problem that reduces cooling and can damage compressor. AC line freezes when evaporator temperature drops below 32F causing moisture to freeze on coil and lines. Causes include restricted airflow due to dirty air filter, dirty evaporator coil, blocked vents, or blower motor failure reducing warm air over coil, causing coil to get too cold and freeze. Low refrigerant charge due to leak causes lower pressure and lower temperature in evaporator, leading to freezing, as less refrigerant absorbs less heat. Faulty TXV or piston metering device stuck closed starves evaporator causing freezing. Running AC when outdoor temperature too low below 60F can cause freezing. Also dirty air filter is most common cause. To fix, turn off AC to let ice thaw, check and replace air filter, clean evaporator coil, ensure all vents open and blower working, check for refrigerant leak if freezing returns, call technician to check charge and metering device. Do not run AC while frozen as it can damage compressor.