What Is a Pollen Filter (Cabin Air Filter)?
The pollen filter — also called the cabin air filter or microfilter — is a paper or activated carbon filter element located in the ventilation system, typically behind the glove box or under the dashboard. It filters the air drawn in from outside the vehicle before it enters the passenger cabin through the heating, ventilation and air conditioning (HVAC) system, removing pollen, dust, fine particles and in activated carbon variants, gaseous pollutants and odours.
What Does the Pollen Filter (Cabin Air Filter) Do?
The pollen filter protects vehicle occupants from airborne allergens and pollutants. A clean pollen filter maintains strong airflow through the ventilation system — a blocked filter reduces airflow, forcing the blower motor to work harder and reducing heating and air conditioning effectiveness. A severely blocked filter can cause the windscreen to demist more slowly, creating a safety issue in cold or wet weather.
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A blocked pollen filter causes reduced airflow from the ventilation vents at all blower speeds, reduced heating and air conditioning effectiveness, musty or unpleasant odours from the vents, and in some vehicles mould growth on the filter element which can cause health problems for allergic occupants.
When Should the Pollen Filter (Cabin Air Filter) Be Replaced?
Pollen filters should be replaced every 12,000 to 15,000 miles or annually — whichever comes first. They are an inexpensive item (typically £10 to £30) that is often overlooked in standard service schedules. Replacement is usually straightforward and can be a DIY job on many vehicles.
If you are experiencing symptoms related to your pollen filter (cabin air filter) and are unsure whether it needs replacing, a free MotorLoom fault scan can help identify whether the component is likely at fault - giving you the most likely cause and estimated repair cost before you visit a garage.
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Related Parts
Other components that work alongside or are related to the pollen filter (cabin air filter):