Blog / Air filter vs cabin filter

Fluids & Filters · 3 min read

Air Filter vs Cabin Filter: What's the Difference?

These two filters get confused constantly, largely because they have similar names, but they do completely different jobs in completely different parts of the car.

The engine air filter

Sits in the engine bay and filters the air the engine actually burns as part of combustion. A clogged engine air filter restricts airflow into the engine, which can reduce power, worsen fuel economy, and in severe cases cause the engine to run richer than it should, affecting emissions too. It's usually replaced every 12,000 to 15,000 miles, though it's worth checking sooner if you regularly drive on dusty roads.

The cabin (pollen) filter

Sits inside the car's ventilation system, usually behind the glovebox, and filters the air that comes through the heater and air conditioning into the cabin. A clogged cabin filter causes reduced airflow from the vents, musty smells, and can contribute to a fogged-up windscreen taking longer to clear, since airflow through the system is reduced. It's typically replaced every 12,000 to 15,000 miles or annually, whichever comes first.

Why both matter for different reasons

The engine air filter affects how the engine runs and performs. The cabin filter affects air quality and comfort inside the car, and matters more than people expect for anyone with allergies, since it's specifically designed to catch pollen and particulates before they reach the cabin.

Checking and replacing them yourself

Both are among the easier DIY jobs on most cars, usually accessible without tools or with just a screwdriver, and significantly cheaper to do yourself than as a garage labour charge, provided you can find the correct filter for your specific model.