A clogged air conditioner filter typically presents three classic symptoms. The accumulation of dust and particles in the filter blocks the airflow, affecting the normal circulation of the air conditioning system. Second, musty or strange odors may appear inside the car, as the contaminated filter cannot effectively filter allergens such as mold spores or pollen from the air. Third, car windows are more prone to fogging or frosting, especially in humid weather, because the clogged filter leads to poor air circulation inside the car, preventing timely discharge of humidity. It is best to replace the filter every 12 to 18 months or every 25,000 kilometres driven. Regular filter replacement not only maintains the efficiency of the air conditioner but also reduces the load on the blower motor, extends the lifespan of the HVAC system, and ensures the air quality inside the car, which is particularly important for passengers with allergic constitutions.
