The answer to 'why is my evaporator coil freezing up' is that a frozen evaporator coil is usually caused by a problem with airflow over the coil or a refrigerant charge issue. Common causes include a dirty air filter, low refrigerant levels, a malfunctioning blower fan, or a problem with the thermostat or refrigerant system.
If the evaporator coil freezes, it can restrict airflow and lead to further issues like a frozen compressor or water leaks. Addressing the root cause is important to prevent damage and restore proper cooling. Homeowners can try simple DIY troubleshooting like changing the air filter, but should call an HVAC professional if the issue persists or they're unsure of the cause.