A cabin air filter stops contaminants such as dirt, dust, smoke, smog, pollen, mold spores, and exhaust gases from entering the cabin of a vehicle through the heating, ventilation, and air conditioning (HVAC) system. It also keeps out other debris, such as bugs, rodent droppings, and leaves.
Cabin air filters are typically rectangular and made of paper and a mix of other fibrous materials. They have pleats to better catch the contaminants.
When air passes over the cabin air filter, debris is trapped by the filter, rather than being pumped into the car. Eventually, that debris builds up, and the filter needs to be changed to continue to work efficiently.
Cabin Air Filter vs. Engine Air Filter
A cabin air filter shouldn’t be confused with your engine’s air filter, although they perform similar functions. The engine’s air filter ensures clean air gets to the engine, while a cabin air filter ensures clean air gets to you.