The AC filter, also known as the cabin air filter, is an air filter whose purpose is to remove contaminants from the air that is ventilated through the vehicle's air conditioning system. They serve to keep the cabin as comfortable as possible for the passengers by removing pollutants such as dust, dirt, and allergens. Similar to an engine air filter, they also become dirty and clogged with use and need to be replaced periodically. When a cabin air filter has become excessively dirty and needs to be replaced, it will usually display a few signs that it is time.
1. Reduced airflow from the AC vents
One of the most common symptoms indicating that a cabin filter is in need of replacement is reduced airflow. Reduced airflow will appear in the form of less air being expelled from the AC system's vents. When the filter is dirty or clogged, less air is able to pass through and the air that is able to pass through requires more effort than normal. Not only will this cause the AC system to work less efficiently, it will also cause the engine to run less efficiently.
2. Reduced power output from the engine
If the cabin air filter is clogged, an additional strain is placed on the AC blower motor. This additional strain will not only cause the blower motor to work harder and blow less air than it is designed to, it will also place an additional strain on the engine due to the higher demand of electricity. In more severe cases the additional strain will result in a noticeable reduction of power when the AC is turned on.
3. Increased dust and allergens in the cabin
Another sign that the cabin air filter needs to be replaced is that you may notice an increased amount of dust and possibly allergens in the cabin, if you are allergic. When a filter is clogged, it is no longer able to filter air efficiently, and the air that does pass through may not be adequately filtered. This may also be a potential sign that the AC filter may have been damaged or torn somehow, and is allowing unfiltered air to enter the cabin.
The AC filter is a simple, but important part of the AC system. Making sure it is replaced when necessary will go a long way in maintaining the comfort and efficiency of your vehicle's AC system. If you suspect that your cabin filter may need to be replaced, this is something that any professional technician, such as one from YourMechanic, should be able to assist you with both quickly and easily.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing AC Air Filter and was authored by Eduardo Ruelas.