The answer to 'air filter freezing up' is that a frozen air filter is typically caused by a problem with the HVAC system, such as low refrigerant levels or a malfunctioning blower fan. Symptoms can include reduced airflow, icy coils, and the filter itself becoming frozen solid. Solutions may involve adjusting the thermostat, checking for airflow obstructions, or having a professional technician diagnose and repair the underlying issue.
It's important not to try to force a frozen filter or coil to thaw, as this can lead to further damage. In most cases, it's best to call an HVAC professional to properly diagnose and fix the problem to prevent further issues or potential safety hazards.