When you turn on the heat or air conditioner, the air that you get from the car vents originates from outside the car. The cabin air filter cleans the air before passing it through the heating or air conditioning system.
The cabin air filter is different from the air filter. The job of the air filter is to clean the air that goes into the engine to burn fuel. The job of the cabin air filter is to clean the air that you get from the vents inside the car. You may have more than one cabin air filter.
Follow the manufacturer’s maintenance schedule and change the cabin air filter as recommended. If you regularly park your car under a tree or near bushes, the cabin air filter(s) will likely suck up debris and leaves, becoming dirtier, faster.
When you turn on the heat, fan, or air conditioning in your vehicle, the air that enters the cabin is taken from outside the car. Before passing through your vents it first goes through the cabin air filter, which captures much of the dust, dirt, and harmful pollutants in the air. A functioning cabin air filter assures that the air coming through your vents is clean.
When the cabin air filter stops working, the air that enters your vents is unfiltered and can be harmful to breathe. A dirty cabin air filter also obstructs the flow of air to the vents, which will lower the power of your heating or air conditioning system.