Just like your air filter at home, cabin filters for cars should be replaced once or twice a year. There are several factors that can impact the performance of the cabin air filters. Dust, road grime, leaves and other particulate matter that clogs the filter and slows the air flow. Humidity and moisture can be other factors that can impact the performance of the filter.

In reality, However, anytime you feel that the flow of air inside the car is being disrupted or weakened, it is time to replace the cabin filter. Some would prefer to replace the filter after pollen season and ahead of the hot summer and or after fall when dry leaves and debris are over. This is to ensure proper flow of cold air in the summer or hot air for defrosting in the winter.   Others prefer to replace the filter ahead of the allergy season. In essence, this is not a “mechanical” car question, it Is rather a judgment call that drivers and passengers need to make any time the flow of air inside the car is weekend weakened or a musty odor is sensed.