If you don't replace your cabin air filter, the filter will become increasingly clogged with dirt and debris, compromising the efficiency of your car's filter and HVAC system. The volume of air in the passenger compartment will be continuously reduced, resulting in bad odors inside your car. The most notable consequence of not replacing the cabin air filter is a decrease in air quality. Your car will be exposed to all pollutants thrown on the road by other vehicles, such as diesel fumes and burnt oil, as well as allergens that enter without being cleaned.
Most car models manufactured after 2000 are equipped with cabin air filters (some luxury models even have more than one); however, older models may not have them at all. If you don't have a fully functioning air filter, harmful fumes, pollen particles, dust, or harsh airborne chemicals can and will enter the cabin of your vehicle. When updating your car's maintenance records, you'll see that replacing the cabin air filter is recommended. This is because when the air filter has passed its replacement time, it affects the cabin air temperature, which depends on a constant flow of air passing through the heater core, the evaporator, or both components.
Without this restriction, a host of problems can arise. One common symptom of a clogged or dirty cabin air filter is an increase in noise from the air conditioning system. This is because it has to work harder to provide sufficient airflow. Some luxury brands charge more for their parts and require that you only buy cabin air filters from their brand; however, you can usually buy a generic cabin air filter at your local automotive store.
If you have changed an air filter in your air conditioning unit or air exchange unit or even in your vacuum cleaner, you can probably change the air filter in your car's cabin. Another common sign that an air filter needs to be changed is when you notice odors in your vehicle. If your cabin air filter isn't replaced regularly, you run the risk of inhaling hazardous particles while you're inside the vehicle. A cabin air filter cleans the air entering the cabin of dust, dirt, exhaust gases and even particles that cause an allergenic reaction if they enter the respiratory tract.
While the cabin air filter is easy to access, be careful not to break any of the clips or pins that hold it.