What is a Cabin Air Filter?
Cabin air filters first appeared back in the mid-1980s. The earliest applications were on Audi and other European makes. Today, about 80 percent of all new import and domestic vehicles have a cabin air filter.
Cabin air filters are installed to keep the air in the vehicle clean and odor free. The filter can trap pollen, dust, smoke and other pollutants that would otherwise enter the vehicle through the outside vents causing allergy and discomfort due to undesirable smells.
Most of the cabin air filters are highly efficient and have electro-statically charged fibers that do a great job of trapping even the smallest particles down to 0.22 microns. Most cabin air filters will stop 100 percent of all dust particles that are three microns or larger and 95 percent of all particles below three microns.
Most of today’s cabin air filters trap odors and are called charcoal activated cabin filters. These filters have an extra layer of activated carbon that reacts with odors and other airborne pollutants to neutralize them before they enter the vehicle. The charcoal activated filters will also reduce the levels of CO2 (carbon monoxide) and NO2 (oxides of nitrogen) from the emissions of other vehicles on the road. For example; vehicles that do not have a carbon activated filter and are in rush hour traffic, will have up to three times the CO2 levels inside the vehicle than outside.
Cabin air filters serves many other purposes including preventing foreign objects like leaves, small animals, moisture and other debris from entering the heater and AC system. This will in turn provide a bit of insurance from objects entering into the heater compartment and jamming controls and switches. Keeping moisture out of the heater system will also help reduce the growth of mold and other microbes on the A/C evaporator.
When Should I replace the Cabin Filter?
The recommended replacement interval for a cabin air filter depends on the type of filter being replaced. (Carbon or paper) and the cabins filter exposure to the environment and mileage driven.
Most vehicle manufacturers do recommend replacing a paper or carbon activated filter once a year or every 12,000 to 15,000 miles to keep the cabin filter working at its highest efficiency. We recommend checking the vehicle owner’s manual for specific replacement recommendations.
Most cabin air filters are flat rectangle panel type filters. Some vehicle cabin filters have unusual shapes so they will fit the heater inlet ducting. You can find the cabin filter on most vehicles behind the glove box or at the base of the windshield under the hood in the cowl area over the heater inlet duct. On some Mercedes, BMW, and Audi vehicles there will be two filters that need to be replaced.
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